21520522 has 4 divisors (see below), whose sum is σ = 32280786. Its totient is φ = 10760260.

The previous prime is 21520519. The next prime is 21520529. The reversal of 21520522 is 22502512.

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

It can be written as a sum of positive squares in only one way, i.e., 17313921 + 4206601 = 4161^2 + 2051^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21520522.

It is not an unprimeable number, because it can be changed into a prime (21520529) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5380129 + ... + 5380132.

Almost surely, 2^21520522 is an apocalyptic number.

21520522 is a deficient number, since it is larger than the sum of its proper divisors (10760264).

21520522 is a wasteful number, since it uses less digits than its factorization.

21520522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10760263.

The product of its (nonzero) digits is 400, while the sum is 19.

The square root of 21520522 is about 4639.0216641012. The cubic root of 21520522 is about 278.1533322482.

The spelling of 21520522 in words is "twenty-one million, five hundred twenty thousand, five hundred twenty-two".