21202131 has 4 divisors (see below), whose sum is σ = 28269512. Its totient is φ = 14134752.

The previous prime is 21202127. The next prime is 21202133. The reversal of 21202131 is 13120212.

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

It is not a de Polignac number, because 21202131 - 2² = 21202127 is a prime.

It is a super-2 number, since 2×21202131² = 899060717882322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21202133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3533686 + ... + 3533691.

It is an arithmetic number, because the mean of its divisors is an integer number (7067378).

Almost surely, 2^21202131 is an apocalyptic number.

21202131 is a deficient number, since it is larger than the sum of its proper divisors (7067381).

21202131 is an equidigital number, since it uses as much as digits as its factorization.

21202131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7067380.

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 21202131 is about 4604.5771792858. The cubic root of 21202131 is about 276.7747738031.

Adding to 21202131 its reverse (13120212), we get a palindrome (34322343).

The spelling of 21202131 in words is "twenty-one million, two hundred two thousand, one hundred thirty-one".