261630000 has 500 divisors, whose sum is σ = 1054631160. Its totient is φ = 62208000.

The previous prime is 261629989. The next prime is 261630001. The reversal of 261630000 is 36162.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (500).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261630001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 99 ways as a sum of consecutive naturals, for example, 13769991 + ... + 13770009.

Almost surely, 2^261630000 is an apocalyptic number.

261630000 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 261630000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (527315580).

261630000 is an abundant number, since it is smaller than the sum of its proper divisors (793001160).

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

261630000 is a wasteful number, since it uses less digits than its factorization.

261630000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76 (or 46 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 261630000 is about 16174.9806800503. The cubic root of 261630000 is about 639.5814320402.

Adding to 261630000 its reverse (36162), we get a palindrome (261666162).

The spelling of 261630000 in words is "two hundred sixty-one million, six hundred thirty thousand".