261440646 has 32 divisors (see below), whose sum is σ = 551197440. Its totient is φ = 82440864.

The previous prime is 261440629. The next prime is 261440651. The reversal of 261440646 is 646044162.

It is a super-2 number, since 2×261440646² = 136702422761794632, which contains 22 as substring.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 110896 + ... + 113228.

It is an arithmetic number, because the mean of its divisors is an integer number (17224920).

Almost surely, 2^261440646 is an apocalyptic number.

261440646 is an abundant number, since it is smaller than the sum of its proper divisors (289756794).

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

261440646 is a wasteful number, since it uses less digits than its factorization.

261440646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3340.

The product of its (nonzero) digits is 27648, while the sum is 33.

The square root of 261440646 is about 16169.1263214807. The cubic root of 261440646 is about 639.4270963610.

The spelling of 261440646 in words is "two hundred sixty-one million, four hundred forty thousand, six hundred forty-six".