21613529 has 12 divisors (see below), whose sum is σ = 25155264. Its totient is φ = 18191352.

The previous prime is 21613517. The next prime is 21613577. The reversal of 21613529 is 92531612.

It is a de Polignac number, because none of the positive numbers 2^k-21613529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21613129) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 23924 + ... + 24810.

It is an arithmetic number, because the mean of its divisors is an integer number (2096272).

Almost surely, 2^21613529 is an apocalyptic number.

It is an amenable number.

21613529 is a deficient number, since it is larger than the sum of its proper divisors (3541735).

21613529 is an frugal number, since it uses more digits than its factorization.

21613529 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1012 (or 953 counting only the distinct ones).

The product of its digits is 3240, while the sum is 29.

The square root of 21613529 is about 4649.0352762697. The cubic root of 21613529 is about 278.5534623772.

The spelling of 21613529 in words is "twenty-one million, six hundred thirteen thousand, five hundred twenty-nine".