261421177017210 has 256 divisors, whose sum is σ = 762268175843328. Its totient is φ = 56012995584000.

The previous prime is 261421177017191. The next prime is 261421177017241. The reversal of 261421177017210 is 12710771124162.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1375436685 + ... + 1375626735.

It is an arithmetic number, because the mean of its divisors is an integer number (2977610061888).

Almost surely, 2^{261421177017210} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261421177017210, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (381134087921664).

261421177017210 is an abundant number, since it is smaller than the sum of its proper divisors (500846998826118).

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

261421177017210 is a wasteful number, since it uses less digits than its factorization.

261421177017210 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191629.

The product of its (nonzero) digits is 65856, while the sum is 42.

The spelling of 261421177017210 in words is "two hundred sixty-one trillion, four hundred twenty-one billion, one hundred seventy-seven million, seventeen thousand, two hundred ten".