21064761 has 12 divisors (see below), whose sum is σ = 30487600. Its totient is φ = 14015160.

The previous prime is 21064753. The next prime is 21064781. The reversal of 21064761 is 16746012.

21064761 is a `hidden beast` number, since 2 + 10 + 647 + 6 + 1 = 666.

It is not a de Polignac number, because 21064761 - 2³ = 21064753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21064781) by changing a digit.

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 in 11 ways as a sum of consecutive naturals, for example, 3090 + ... + 7188.

Almost surely, 2^21064761 is an apocalyptic number.

It is an amenable number.

21064761 is a deficient number, since it is larger than the sum of its proper divisors (9422839).

21064761 is a wasteful number, since it uses less digits than its factorization.

21064761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4676 (or 4673 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 21064761 is about 4589.6362600973. The cubic root of 21064761 is about 276.1757308725.

The spelling of 21064761 in words is "twenty-one million, sixty-four thousand, seven hundred sixty-one".