21463939 has 16 divisors (see below), whose sum is σ = 26196480. Its totient is φ = 17176320.

The previous prime is 21463933. The next prime is 21463943. The reversal of 21463939 is 93936412.

It is not a de Polignac number, because 21463939 - 2³ = 21463931 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21463898 and 21463907.

It is not an unprimeable number, because it can be changed into a prime (21463931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8307 + ... + 10579.

It is an arithmetic number, because the mean of its divisors is an integer number (1637280).

Almost surely, 2^21463939 is an apocalyptic number.

21463939 is a deficient number, since it is larger than the sum of its proper divisors (4732541).

21463939 is a wasteful number, since it uses less digits than its factorization.

21463939 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2370.

The product of its digits is 34992, while the sum is 37.

The square root of 21463939 is about 4632.9190582180. The cubic root of 21463939 is about 277.9093393449.

The spelling of 21463939 in words is "twenty-one million, four hundred sixty-three thousand, nine hundred thirty-nine".