21400863 has 16 divisors (see below), whose sum is σ = 31526400. Its totient is φ = 12804480.

The previous prime is 21400849. The next prime is 21400877. The reversal of 21400863 is 36800412.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21400849) and next prime (21400877).

It is not a de Polignac number, because 21400863 - 2⁵ = 21400831 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21400823) 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 15 ways as a sum of consecutive naturals, for example, 1498 + ... + 6711.

It is an arithmetic number, because the mean of its divisors is an integer number (1970400).

Almost surely, 2^21400863 is an apocalyptic number.

21400863 is a deficient number, since it is larger than the sum of its proper divisors (10125537).

21400863 is a wasteful number, since it uses less digits than its factorization.

21400863 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8302.

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 21400863 is about 4626.1066784068. The cubic root of 21400863 is about 277.6368418507.

The spelling of 21400863 in words is "twenty-one million, four hundred thousand, eight hundred sixty-three".