21613031 has 8 divisors (see below), whose sum is σ = 24603264. Its totient is φ = 18793720.

The previous prime is 21613019. The next prime is 21613043. The reversal of 21613031 is 13031612.

It is an interprime number because it is at equal distance from previous prime (21613019) and next prime (21613043).

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

It is a de Polignac number, because none of the positive numbers 2^k-21613031 is a prime.

It is a super-2 number, since 2×21613031² = 934246218013922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21613931) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42461 + ... + 42966.

It is an arithmetic number, because the mean of its divisors is an integer number (3075408).

Almost surely, 2^21613031 is an apocalyptic number.

21613031 is a deficient number, since it is larger than the sum of its proper divisors (2990233).

21613031 is a wasteful number, since it uses less digits than its factorization.

21613031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85461.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 21613031 is about 4648.9817164622. The cubic root of 21613031 is about 278.5513229658.

Adding to 21613031 its reverse (13031612), we get a palindrome (34644643).

The spelling of 21613031 in words is "twenty-one million, six hundred thirteen thousand, thirty-one".