21630534 has 32 divisors (see below), whose sum is σ = 46255104. Its totient is φ = 6726720.

The previous prime is 21630527. The next prime is 21630541. The reversal of 21630534 is 43503612.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21630527) and next prime (21630541).

It is a super-2 number, since 2×21630534² = 935760002250312, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3747 + ... + 7569.

It is an arithmetic number, because the mean of its divisors is an integer number (1445472).

Almost surely, 2^21630534 is an apocalyptic number.

21630534 is an abundant number, since it is smaller than the sum of its proper divisors (24624570).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21630534 is a wasteful number, since it uses less digits than its factorization.

21630534 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3892.

The product of its (nonzero) digits is 2160, while the sum is 24.

The square root of 21630534 is about 4650.8637907382. The cubic root of 21630534 is about 278.6264962611.

The spelling of 21630534 in words is "twenty-one million, six hundred thirty thousand, five hundred thirty-four".