20543664 has 20 divisors (see below), whose sum is σ = 53071256. Its totient is φ = 6847872.

The previous prime is 20543657. The next prime is 20543671. The reversal of 20543664 is 46634502.

It is an interprime number because it is at equal distance from previous prime (20543657) and next prime (20543671).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 213949 + ... + 214044.

Almost surely, 2^20543664 is an apocalyptic number.

20543664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

20543664 is an abundant number, since it is smaller than the sum of its proper divisors (32527592).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20543664 is a wasteful number, since it uses less digits than its factorization.

20543664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 428004 (or 427998 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 30.

The square root of 20543664 is about 4532.5118863606. The cubic root of 20543664 is about 273.8793579748.

The spelling of 20543664 in words is "twenty million, five hundred forty-three thousand, six hundred sixty-four".