21473431 has 16 divisors (see below), whose sum is σ = 26692416. Its totient is φ = 16851456.

The previous prime is 21473423. The next prime is 21473437. The reversal of 21473431 is 13437412.

It is a cyclic number.

It is not a de Polignac number, because 21473431 - 2³ = 21473423 is a prime.

It is a super-2 number, since 2×21473431² = 922216477823522, 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 = 21473396 and 21473405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21473437) 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, 1965 + ... + 6841.

It is an arithmetic number, because the mean of its divisors is an integer number (1668276).

Almost surely, 2^21473431 is an apocalyptic number.

21473431 is a deficient number, since it is larger than the sum of its proper divisors (5218985).

21473431 is a wasteful number, since it uses less digits than its factorization.

21473431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4938.

The product of its digits is 2016, while the sum is 25.

The square root of 21473431 is about 4633.9433531281. The cubic root of 21473431 is about 277.9502999330.

It can be divided in two parts, 21473 and 431, that added together give a square (21904 = 148²).

The spelling of 21473431 in words is "twenty-one million, four hundred seventy-three thousand, four hundred thirty-one".