20401864 has 32 divisors (see below), whose sum is σ = 44049600. Its totient is φ = 8677440.

The previous prime is 20401861. The next prime is 20401867. The reversal of 20401864 is 46810402.

It is an interprime number because it is at equal distance from previous prime (20401861) and next prime (20401867).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20401861) by changing a digit.

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, 6474 + ... + 9094.

It is an arithmetic number, because the mean of its divisors is an integer number (1376550).

Almost surely, 2^20401864 is an apocalyptic number.

It is an amenable number.

20401864 is an abundant number, since it is smaller than the sum of its proper divisors (23647736).

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

20401864 is a wasteful number, since it uses less digits than its factorization.

20401864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2773 (or 2769 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 25.

The square root of 20401864 is about 4516.8422598094. The cubic root of 20401864 is about 273.2477635507.

The spelling of 20401864 in words is "twenty million, four hundred one thousand, eight hundred sixty-four".