21731522 has 4 divisors (see below), whose sum is σ = 32597286. Its totient is φ = 10865760.

The previous prime is 21731519. The next prime is 21731533. The reversal of 21731522 is 22513712.

It is a happy number.

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., 14661241 + 7070281 = 3829^2 + 2659^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5432879 + ... + 5432882.

Almost surely, 2^21731522 is an apocalyptic number.

21731522 is a deficient number, since it is larger than the sum of its proper divisors (10865764).

21731522 is a wasteful number, since it uses less digits than its factorization.

21731522 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10865763.

The product of its digits is 840, while the sum is 23.

The square root of 21731522 is about 4661.7080560670. The cubic root of 21731522 is about 279.0594375835.

The spelling of 21731522 in words is "twenty-one million, seven hundred thirty-one thousand, five hundred twenty-two".