20400931 has 8 divisors (see below), whose sum is σ = 21434400. Its totient is φ = 19379712.

The previous prime is 20400869. The next prime is 20400959. The reversal of 20400931 is 13900402.

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 20400931 - 2⁷ = 20400803 is a prime.

It is a super-2 number, since 2×20400931² = 832395971333522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20400899 and 20400908.

It is not an unprimeable number, because it can be changed into a prime (20400031) 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, 451 + ... + 6403.

It is an arithmetic number, because the mean of its divisors is an integer number (2679300).

Almost surely, 2^20400931 is an apocalyptic number.

20400931 is a deficient number, since it is larger than the sum of its proper divisors (1033469).

20400931 is a wasteful number, since it uses less digits than its factorization.

20400931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6125.

The product of its (nonzero) digits is 216, while the sum is 19.

The square root of 20400931 is about 4516.7389785109. The cubic root of 20400931 is about 273.2435981789.

The spelling of 20400931 in words is "twenty million, four hundred thousand, nine hundred thirty-one".