64503561 has 4 divisors (see below), whose sum is σ = 86004752. Its totient is φ = 43002372.

The previous prime is 64503539. The next prime is 64503563. The reversal of 64503561 is 16530546.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 64503561 - 2⁶ = 64503497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (64503563) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10750591 + ... + 10750596.

It is an arithmetic number, because the mean of its divisors is an integer number (21501188).

Almost surely, 2^64503561 is an apocalyptic number.

It is an amenable number.

64503561 is a deficient number, since it is larger than the sum of its proper divisors (21501191).

64503561 is a wasteful number, since it uses less digits than its factorization.

64503561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21501190.

The product of its (nonzero) digits is 10800, while the sum is 30.

The square root of 64503561 is about 8031.4108972210. The cubic root of 64503561 is about 401.0463459305.

It can be divided in two parts, 6450 and 3561, that added together give a triangular number (10011 = T₁₄₁).

The spelling of 64503561 in words is "sixty-four million, five hundred three thousand, five hundred sixty-one".