64261561 has 16 divisors (see below), whose sum is σ = 80438400. Its totient is φ = 49978368.

The previous prime is 64261541. The next prime is 64261573. The reversal of 64261561 is 16516246.

It is a cyclic number.

It is not a de Polignac number, because 64261561 - 2⁵ = 64261529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (64261501) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 616 + ... + 11353.

It is an arithmetic number, because the mean of its divisors is an integer number (5027400).

Almost surely, 2^64261561 is an apocalyptic number.

It is an amenable number.

64261561 is a deficient number, since it is larger than the sum of its proper divisors (16176839).

64261561 is a wasteful number, since it uses less digits than its factorization.

64261561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12048.

The product of its digits is 8640, while the sum is 31.

The square root of 64261561 is about 8016.3308938691. The cubic root of 64261561 is about 400.5441780898.

The spelling of 64261561 in words is "sixty-four million, two hundred sixty-one thousand, five hundred sixty-one".