21290131 has 4 divisors (see below), whose sum is σ = 21590064. Its totient is φ = 20990200.

The previous prime is 21290119. The next prime is 21290141. The reversal of 21290131 is 13109212.

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

It is a cyclic number.

It is not a de Polignac number, because 21290131 - 2¹¹ = 21288083 is a prime.

It is a super-2 number, since 2×21290131² = 906539355994322, 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 = 21290099 and 21290108.

It is not an unprimeable number, because it can be changed into a prime (21290141) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 149860 + ... + 150001.

It is an arithmetic number, because the mean of its divisors is an integer number (5397516).

Almost surely, 2^21290131 is an apocalyptic number.

21290131 is a deficient number, since it is larger than the sum of its proper divisors (299933).

21290131 is an equidigital number, since it uses as much as digits as its factorization.

21290131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 299932.

The product of its (nonzero) digits is 108, while the sum is 19.

The square root of 21290131 is about 4614.1229935926. The cubic root of 21290131 is about 277.1571655635.

Adding to 21290131 its reverse (13109212), we get a palindrome (34399343).

The spelling of 21290131 in words is "twenty-one million, two hundred ninety thousand, one hundred thirty-one".