21220131 has 32 divisors (see below), whose sum is σ = 32140800. Its totient is φ = 12372480.

The previous prime is 21220109. The next prime is 21220153. The reversal of 21220131 is 13102212.

It is an interprime number because it is at equal distance from previous prime (21220109) and next prime (21220153).

It is not a de Polignac number, because 21220131 - 2¹¹ = 21218083 is a prime.

It is a super-2 number, since 2×21220131² = 900587919314322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21220231) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 58930 + ... + 59288.

It is an arithmetic number, because the mean of its divisors is an integer number (1004400).

Almost surely, 2^21220131 is an apocalyptic number.

21220131 is a deficient number, since it is larger than the sum of its proper divisors (10920669).

21220131 is a wasteful number, since it uses less digits than its factorization.

21220131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 459.

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

The square root of 21220131 is about 4606.5313414759. The cubic root of 21220131 is about 276.8530762585.

Adding to 21220131 its reverse (13102212), we get a palindrome (34322343).

The spelling of 21220131 in words is "twenty-one million, two hundred twenty thousand, one hundred thirty-one".