261721152000 has 1920 divisors, whose sum is σ = 1231304405760. Its totient is φ = 54190080000.

The previous prime is 261721151969. The next prime is 261721152001. The reversal of 261721152000 is 251127162.

261721152000 is a `hidden beast` number, since 2 + 61 + 72 + 11 + 520 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1920).

It is a super-2 number, since 2×261721152000² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (261721152001) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 931391860 + ... + 931392140.

It is an arithmetic number, because the mean of its divisors is an integer number (641304378).

Almost surely, 2^261721152000 is an apocalyptic number.

261721152000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261721152000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (615652202880).

261721152000 is an abundant number, since it is smaller than the sum of its proper divisors (969583253760).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261721152000 is a wasteful number, since it uses less digits than its factorization.

261721152000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 348 (or 309 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 27.

Adding to 261721152000 its reverse (251127162), we get a palindrome (261972279162).

The spelling of 261721152000 in words is "two hundred sixty-one billion, seven hundred twenty-one million, one hundred fifty-two thousand".