21472531 has 2 divisors, whose sum is σ = 21472532. Its totient is φ = 21472530.

The previous prime is 21472483. The next prime is 21472537. The reversal of 21472531 is 13527412.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21472531 - 2⁷ = 21472403 is a prime.

It is a super-2 number, since 2×21472531² = 922139175091922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21472496 and 21472505.

It is not a weakly prime, because it can be changed into another prime (21472537) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10736265 + 10736266.

It is an arithmetic number, because the mean of its divisors is an integer number (10736266).

Almost surely, 2^21472531 is an apocalyptic number.

21472531 is a deficient number, since it is larger than the sum of its proper divisors (1).

21472531 is an equidigital number, since it uses as much as digits as its factorization.

21472531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1680, while the sum is 25.

The square root of 21472531 is about 4633.8462425937. The cubic root of 21472531 is about 277.9464167038.

Adding to 21472531 its reverse (13527412), we get a palindrome (34999943).

The spelling of 21472531 in words is "twenty-one million, four hundred seventy-two thousand, five hundred thirty-one".