261943731840 has 512 divisors, whose sum is σ = 985310208000. Its totient is φ = 57940033536.

The previous prime is 261943731811. The next prime is 261943731853. The reversal of 261943731840 is 48137349162.

It is a super-2 number, since 2×261943731840² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 261943731840.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 98957397 + ... + 98960043.

It is an arithmetic number, because the mean of its divisors is an integer number (1924434000).

Almost surely, 2^261943731840 is an apocalyptic number.

261943731840 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 261943731840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (492655104000).

261943731840 is an abundant number, since it is smaller than the sum of its proper divisors (723366476160).

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

261943731840 is a wasteful number, since it uses less digits than its factorization.

261943731840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2912 (or 2900 counting only the distinct ones).

The product of its (nonzero) digits is 870912, while the sum is 48.

The spelling of 261943731840 in words is "two hundred sixty-one billion, nine hundred forty-three million, seven hundred thirty-one thousand, eight hundred forty".