21651522 has 16 divisors (see below), whose sum is σ = 43349472. Its totient is φ = 7209440.

The previous prime is 21651517. The next prime is 21651529. The reversal of 21651522 is 22515612.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21651492 and 21651501.

It is not an unprimeable number, because it can be changed into a prime (21651529) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8278 + ... + 10574.

It is an arithmetic number, because the mean of its divisors is an integer number (2709342).

Almost surely, 2^21651522 is an apocalyptic number.

21651522 is an abundant number, since it is smaller than the sum of its proper divisors (21697950).

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

21651522 is a wasteful number, since it uses less digits than its factorization.

21651522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3873.

The product of its digits is 1200, while the sum is 24.

The square root of 21651522 is about 4653.1195987208. The cubic root of 21651522 is about 278.7165837667.

The spelling of 21651522 in words is "twenty-one million, six hundred fifty-one thousand, five hundred twenty-two".