21145131 has 48 divisors (see below), whose sum is σ = 37459968. Its totient is φ = 11664000.

The previous prime is 21145109. The next prime is 21145141. The reversal of 21145131 is 13154112.

21145131 is a `hidden beast` number, since 211 + 451 + 3 + 1 = 666.

It is not a de Polignac number, because 21145131 - 2⁶ = 21145067 is a prime.

It is a super-2 number, since 2×21145131² = 894233130014322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21145141) 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 47 ways as a sum of consecutive naturals, for example, 52531 + ... + 52931.

It is an arithmetic number, because the mean of its divisors is an integer number (780416).

Almost surely, 2^21145131 is an apocalyptic number.

21145131 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21145131 is a deficient number, since it is larger than the sum of its proper divisors (16314837).

21145131 is an equidigital number, since it uses as much as digits as its factorization.

21145131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 454 (or 442 counting only the distinct ones).

The product of its digits is 120, while the sum is 18.

The square root of 21145131 is about 4598.3835203254. The cubic root of 21145131 is about 276.5265232719.

Adding to 21145131 its reverse (13154112), we get a palindrome (34299243).

The spelling of 21145131 in words is "twenty-one million, one hundred forty-five thousand, one hundred thirty-one".