21469531 has 4 divisors (see below), whose sum is σ = 21487312. Its totient is φ = 21451752.

The previous prime is 21469517. The next prime is 21469543. The reversal of 21469531 is 13596412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21469531 - 2¹¹ = 21467483 is a prime.

It is a super-2 number, since 2×21469531² = 921881522719922, 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 = 21469493 and 21469502.

It is not an unprimeable number, because it can be changed into a prime (21469571) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6936 + ... + 9541.

It is an arithmetic number, because the mean of its divisors is an integer number (5371828).

Almost surely, 2^21469531 is an apocalyptic number.

21469531 is a deficient number, since it is larger than the sum of its proper divisors (17781).

21469531 is a wasteful number, since it uses less digits than its factorization.

21469531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17780.

The product of its digits is 6480, while the sum is 31.

The square root of 21469531 is about 4633.5225261134. The cubic root of 21469531 is about 277.9334718226.

The spelling of 21469531 in words is "twenty-one million, four hundred sixty-nine thousand, five hundred thirty-one".