21580131 has 4 divisors (see below), whose sum is σ = 28773512. Its totient is φ = 14386752.

The previous prime is 21580129. The next prime is 21580133. The reversal of 21580131 is 13108512.

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

It is an interprime number because it is at equal distance from previous prime (21580129) and next prime (21580133).

It is not a de Polignac number, because 21580131 - 2¹ = 21580129 is a prime.

It is a super-2 number, since 2×21580131² = 931404107954322, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21580098 and 21580107.

It is not an unprimeable number, because it can be changed into a prime (21580133) 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, 3596686 + ... + 3596691.

It is an arithmetic number, because the mean of its divisors is an integer number (7193378).

Almost surely, 2^21580131 is an apocalyptic number.

21580131 is a deficient number, since it is larger than the sum of its proper divisors (7193381).

21580131 is an equidigital number, since it uses as much as digits as its factorization.

21580131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7193380.

The product of its (nonzero) digits is 240, while the sum is 21.

The square root of 21580131 is about 4645.4419595987. The cubic root of 21580131 is about 278.4099114791.

Adding to 21580131 its reverse (13108512), we get a palindrome (34688643).

The spelling of 21580131 in words is "twenty-one million, five hundred eighty thousand, one hundred thirty-one".