64724991 has 4 divisors (see below), whose sum is σ = 86299992. Its totient is φ = 43149992.

The previous prime is 64724987. The next prime is 64724999. The reversal of 64724991 is 19942746.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 64724991 - 2² = 64724987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64724999) 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, 10787496 + ... + 10787501.

It is an arithmetic number, because the mean of its divisors is an integer number (21574998).

Almost surely, 2^64724991 is an apocalyptic number.

64724991 is a deficient number, since it is larger than the sum of its proper divisors (21575001).

64724991 is a wasteful number, since it uses less digits than its factorization.

64724991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21575000.

The product of its digits is 108864, while the sum is 42.

The square root of 64724991 is about 8045.1843359863. The cubic root of 64724991 is about 401.5047302856.

The spelling of 64724991 in words is "sixty-four million, seven hundred twenty-four thousand, nine hundred ninety-one".