21237772 has 6 divisors (see below), whose sum is σ = 37166108. Its totient is φ = 10618884.

The previous prime is 21237767. The next prime is 21237781. The reversal of 21237772 is 27773212.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2654718 + ... + 2654725.

Almost surely, 2^21237772 is an apocalyptic number.

It is an amenable number.

21237772 is a deficient number, since it is larger than the sum of its proper divisors (15928336).

21237772 is a wasteful number, since it uses less digits than its factorization.

21237772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5309447 (or 5309445 counting only the distinct ones).

The product of its digits is 8232, while the sum is 31.

The square root of 21237772 is about 4608.4457249706. The cubic root of 21237772 is about 276.9297740625.

The spelling of 21237772 in words is "twenty-one million, two hundred thirty-seven thousand, seven hundred seventy-two".