21719564 has 6 divisors (see below), whose sum is σ = 38009244. Its totient is φ = 10859780.

The previous prime is 21719563. The next prime is 21719573. The reversal of 21719564 is 46591712.

It is not an unprimeable number, because it can be changed into a prime (21719563) 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 as a sum of consecutive naturals, namely, 2714942 + ... + 2714949.

It is an arithmetic number, because the mean of its divisors is an integer number (6334874).

Almost surely, 2^21719564 is an apocalyptic number.

It is an amenable number.

21719564 is a deficient number, since it is larger than the sum of its proper divisors (16289680).

21719564 is a wasteful number, since it uses less digits than its factorization.

21719564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5429895 (or 5429893 counting only the distinct ones).

The product of its digits is 15120, while the sum is 35.

The square root of 21719564 is about 4660.4253024805. The cubic root of 21719564 is about 279.0082430558.

The spelling of 21719564 in words is "twenty-one million, seven hundred nineteen thousand, five hundred sixty-four".