21302131 has 8 divisors (see below), whose sum is σ = 21797424. Its totient is φ = 20810400.

The previous prime is 21302129. The next prime is 21302143. The reversal of 21302131 is 13120312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21302131 - 2¹ = 21302129 is a prime.

It is a super-2 number, since 2×21302131² = 907561570282322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21302111) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13956 + ... + 15406.

It is an arithmetic number, because the mean of its divisors is an integer number (2724678).

Almost surely, 2^21302131 is an apocalyptic number.

21302131 is a deficient number, since it is larger than the sum of its proper divisors (495293).

21302131 is a wasteful number, since it uses less digits than its factorization.

21302131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1781.

The product of its (nonzero) digits is 36, while the sum is 13.

The square root of 21302131 is about 4615.4231658646. The cubic root of 21302131 is about 277.2092282041.

Adding to 21302131 its reverse (13120312), we get a palindrome (34422443).

The spelling of 21302131 in words is "twenty-one million, three hundred two thousand, one hundred thirty-one".