21147436 has 6 divisors (see below), whose sum is σ = 37008020. Its totient is φ = 10573716.

The previous prime is 21147433. The next prime is 21147479. The reversal of 21147436 is 63474112.

It is not an unprimeable number, because it can be changed into a prime (21147433) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2643426 + ... + 2643433.

Almost surely, 2^21147436 is an apocalyptic number.

It is an amenable number.

21147436 is a deficient number, since it is larger than the sum of its proper divisors (15860584).

21147436 is a wasteful number, since it uses less digits than its factorization.

21147436 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5286863 (or 5286861 counting only the distinct ones).

The product of its digits is 4032, while the sum is 28.

The square root of 21147436 is about 4598.6341450479. The cubic root of 21147436 is about 276.5365708250.

The spelling of 21147436 in words is "twenty-one million, one hundred forty-seven thousand, four hundred thirty-six".