261450317721564 has 72 divisors (see below), whose sum is σ = 662121299745360. Its totient is φ = 86987612854272.

The previous prime is 261450317721547. The next prime is 261450317721589. The reversal of 261450317721564 is 465127713054162.

261450317721564 is a `hidden beast` number, since 2 + 6 + 1 + 4 + 5 + 0 + 3 + 1 + 7 + 72 + 1 + 564 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 261450317721564.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 60775612 + ... + 64935164.

It is an arithmetic number, because the mean of its divisors is an integer number (9196129163130).

Almost surely, 2^{261450317721564} is an apocalyptic number.

It is an amenable number.

261450317721564 is an abundant number, since it is smaller than the sum of its proper divisors (400670982023796).

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

261450317721564 is a wasteful number, since it uses less digits than its factorization.

261450317721564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4162819 (or 4162814 counting only the distinct ones).

The product of its (nonzero) digits is 8467200, while the sum is 54.

The spelling of 261450317721564 in words is "two hundred sixty-one trillion, four hundred fifty billion, three hundred seventeen million, seven hundred twenty-one thousand, five hundred sixty-four".