21019131 has 24 divisors (see below), whose sum is σ = 35509760. Its totient is φ = 11730096.

The previous prime is 21019129. The next prime is 21019151. The reversal of 21019131 is 13191012.

It is not a de Polignac number, because 21019131 - 2¹ = 21019129 is a prime.

It is a super-2 number, since 2×21019131² = 883607735990322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21019151) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1171 + ... + 6588.

Almost surely, 2^21019131 is an apocalyptic number.

21019131 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21019131 is a deficient number, since it is larger than the sum of its proper divisors (14490629).

21019131 is a wasteful number, since it uses less digits than its factorization.

21019131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7815 (or 7812 counting only the distinct ones).

The product of its (nonzero) digits is 54, while the sum is 18.

The square root of 21019131 is about 4584.6625830043. The cubic root of 21019131 is about 275.9761715408.

The spelling of 21019131 in words is "twenty-one million, nineteen thousand, one hundred thirty-one".