20640955 has 8 divisors (see below), whose sum is σ = 24867072. Its totient is φ = 16447488.

The previous prime is 20640937. The next prime is 20640967. The reversal of 20640955 is 55904602.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20640955 - 2⁷ = 20640827 is a prime.

It is a Duffinian 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, 6747 + ... + 9316.

It is an arithmetic number, because the mean of its divisors is an integer number (3108384).

Almost surely, 2^20640955 is an apocalyptic number.

20640955 is a deficient number, since it is larger than the sum of its proper divisors (4226117).

20640955 is a wasteful number, since it uses less digits than its factorization.

20640955 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16325.

The product of its (nonzero) digits is 10800, while the sum is 31.

The square root of 20640955 is about 4543.2317792514. The cubic root of 20640955 is about 274.3110246180.

The spelling of 20640955 in words is "twenty million, six hundred forty thousand, nine hundred fifty-five".