261622864 has 10 divisors (see below), whose sum is σ = 506894330. Its totient is φ = 130811424.

The previous prime is 261622849. The next prime is 261622939. The reversal of 261622864 is 468226162.

It can be written as a sum of positive squares in only one way, i.e., 137077264 + 124545600 = 11708^2 + 11160^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8175699 + ... + 8175730.

It is an arithmetic number, because the mean of its divisors is an integer number (50689433).

Almost surely, 2^261622864 is an apocalyptic number.

It is an amenable number.

261622864 is a deficient number, since it is larger than the sum of its proper divisors (245271466).

261622864 is a wasteful number, since it uses less digits than its factorization.

261622864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16351437 (or 16351431 counting only the distinct ones).

The product of its digits is 55296, while the sum is 37.

The square root of 261622864 is about 16174.7600909565. The cubic root of 261622864 is about 639.5756170921.

The spelling of 261622864 in words is "two hundred sixty-one million, six hundred twenty-two thousand, eight hundred sixty-four".