21020131 has 8 divisors (see below), whose sum is σ = 23246064. Its totient is φ = 18846720.

The previous prime is 21020119. The next prime is 21020159. The reversal of 21020131 is 13102012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21020131 - 2¹⁵ = 20987363 is a prime.

It is a super-2 number, since 2×21020131² = 883691814514322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21020161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12286 + ... + 13891.

It is an arithmetic number, because the mean of its divisors is an integer number (2905758).

Almost surely, 2^21020131 is an apocalyptic number.

21020131 is a deficient number, since it is larger than the sum of its proper divisors (2225933).

21020131 is a wasteful number, since it uses less digits than its factorization.

21020131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26261.

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 21020131 is about 4584.7716409871. The cubic root of 21020131 is about 275.9805480585.

Adding to 21020131 its reverse (13102012), we get a palindrome (34122143).

The spelling of 21020131 in words is "twenty-one million, twenty thousand, one hundred thirty-one".