21131017 has 16 divisors (see below), whose sum is σ = 23170752. Its totient is φ = 19192320.

The previous prime is 21131009. The next prime is 21131029. The reversal of 21131017 is 71013112.

It is not a de Polignac number, because 21131017 - 2³ = 21131009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21131087) 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 15 ways as a sum of consecutive naturals, for example, 100042 + ... + 100252.

It is an arithmetic number, because the mean of its divisors is an integer number (1448172).

Almost surely, 2^21131017 is an apocalyptic number.

It is an amenable number.

21131017 is a deficient number, since it is larger than the sum of its proper divisors (2039735).

21131017 is a wasteful number, since it uses less digits than its factorization.

21131017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 408.

The product of its (nonzero) digits is 42, while the sum is 16.

The square root of 21131017 is about 4596.8485944177. The cubic root of 21131017 is about 276.4649840608.

Adding to 21131017 its reverse (71013112), we get a palindrome (92144129).

The spelling of 21131017 in words is "twenty-one million, one hundred thirty-one thousand, seventeen".