261517572 has 72 divisors (see below), whose sum is σ = 701596896. Its totient is φ = 85131648.

The previous prime is 261517561. The next prime is 261517589. The reversal of 261517572 is 275715162.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 38668 + ... + 44924.

Almost surely, 2^261517572 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 261517572, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (350798448).

261517572 is an abundant number, since it is smaller than the sum of its proper divisors (440079324).

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

261517572 is a wasteful number, since it uses less digits than its factorization.

261517572 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6319 (or 6305 counting only the distinct ones).

The product of its digits is 29400, while the sum is 36.

The square root of 261517572 is about 16171.5049392442. The cubic root of 261517572 is about 639.4898049795.

The spelling of 261517572 in words is "two hundred sixty-one million, five hundred seventeen thousand, five hundred seventy-two".