20641656 has 32 divisors (see below), whose sum is σ = 58976640. Its totient is φ = 5897568.

The previous prime is 20641633. The next prime is 20641661. The reversal of 20641656 is 65614602.

20641656 = T₂₄₂₅ + T₂₄₂₆ + ... + T₂₄₃₁.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 61266 + ... + 61601.

It is an arithmetic number, because the mean of its divisors is an integer number (1843020).

Almost surely, 2^20641656 is an apocalyptic number.

It is an amenable number.

20641656 is an abundant number, since it is smaller than the sum of its proper divisors (38334984).

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

20641656 is a wasteful number, since it uses less digits than its factorization.

20641656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122883 (or 122879 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 20641656 is about 4543.3089263223. The cubic root of 20641656 is about 274.3141299306.

The spelling of 20641656 in words is "twenty million, six hundred forty-one thousand, six hundred fifty-six".