20664742 has 16 divisors (see below), whose sum is σ = 37290240. Its totient is φ = 8390088.

The previous prime is 20664737. The next prime is 20664781. The reversal of 20664742 is 24746602.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38578 + ... + 39109.

It is an arithmetic number, because the mean of its divisors is an integer number (2330640).

Almost surely, 2^20664742 is an apocalyptic number.

20664742 is a deficient number, since it is larger than the sum of its proper divisors (16625498).

20664742 is a wasteful number, since it uses less digits than its factorization.

20664742 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77715.

The product of its (nonzero) digits is 16128, while the sum is 31.

The square root of 20664742 is about 4545.8488756227. The cubic root of 20664742 is about 274.4163577841.

The spelling of 20664742 in words is "twenty million, six hundred sixty-four thousand, seven hundred forty-two".