261538352400 has 240 divisors, whose sum is σ = 903472910144. Its totient is φ = 64290723840.

The previous prime is 261538352363. The next prime is 261538352407. The reversal of 261538352400 is 4253835162.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (240).

It is a super-2 number, since 2×261538352400² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (261538352407) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 11798127 + ... + 11820273.

Almost surely, 2^261538352400 is an apocalyptic number.

261538352400 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 261538352400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (451736455072).

261538352400 is an abundant number, since it is smaller than the sum of its proper divisors (641934557744).

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

261538352400 is a wasteful number, since it uses less digits than its factorization.

261538352400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22938 (or 22927 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 39.

The spelling of 261538352400 in words is "two hundred sixty-one billion, five hundred thirty-eight million, three hundred fifty-two thousand, four hundred".