21602131 has 4 divisors (see below), whose sum is σ = 21641472. Its totient is φ = 21562792.

The previous prime is 21602099. The next prime is 21602137. The reversal of 21602131 is 13120612.

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

It is a cyclic number.

It is not a de Polignac number, because 21602131 - 2⁵ = 21602099 is a prime.

It is a super-2 number, since 2×21602131² = 933304127482322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21602137) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18835 + ... + 19948.

It is an arithmetic number, because the mean of its divisors is an integer number (5410368).

Almost surely, 2^21602131 is an apocalyptic number.

21602131 is a deficient number, since it is larger than the sum of its proper divisors (39341).

21602131 is an equidigital number, since it uses as much as digits as its factorization.

21602131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39340.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 21602131 is about 4647.8092688922. The cubic root of 21602131 is about 278.5044882580.

Adding to 21602131 its reverse (13120612), we get a palindrome (34722743).

The spelling of 21602131 in words is "twenty-one million, six hundred two thousand, one hundred thirty-one".