21250131 has 16 divisors (see below), whose sum is σ = 32793600. Its totient is φ = 11988288.

The previous prime is 21250129. The next prime is 21250133. The reversal of 21250131 is 13105212.

It is an interprime number because it is at equal distance from previous prime (21250129) and next prime (21250133).

It is not a de Polignac number, because 21250131 - 2¹ = 21250129 is a prime.

It is a super-2 number, since 2×21250131² = 903136135034322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21250131.

It is not an unprimeable number, because it can be changed into a prime (21250133) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4746 + ... + 8063.

It is an arithmetic number, because the mean of its divisors is an integer number (2049600).

Almost surely, 2^21250131 is an apocalyptic number.

21250131 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21250131 is a deficient number, since it is larger than the sum of its proper divisors (11543469).

21250131 is a wasteful number, since it uses less digits than its factorization.

21250131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12898.

The product of its (nonzero) digits is 60, while the sum is 15.

The square root of 21250131 is about 4609.7864375695. The cubic root of 21250131 is about 276.9834820093.

Adding to 21250131 its reverse (13105212), we get a palindrome (34355343).

The spelling of 21250131 in words is "twenty-one million, two hundred fifty thousand, one hundred thirty-one".