21113131 has 8 divisors (see below), whose sum is σ = 23521680. Its totient is φ = 18816672.

The previous prime is 21113119. The next prime is 21113153. The reversal of 21113131 is 13131112.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21113131 is a prime.

It is a super-2 number, since 2×21113131² = 891528601246322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is not an unprimeable number, because it can be changed into a prime (21113101) 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, 27625 + ... + 28378.

It is an arithmetic number, because the mean of its divisors is an integer number (2940210).

Almost surely, 2^21113131 is an apocalyptic number.

21113131 is a deficient number, since it is larger than the sum of its proper divisors (2408549).

21113131 is a wasteful number, since it uses less digits than its factorization.

21113131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56045.

The product of its digits is 18, while the sum is 13.

The square root of 21113131 is about 4594.9027193184. The cubic root of 21113131 is about 276.3869589705.

Adding to 21113131 its reverse (13131112), we get a palindrome (34244243).

The spelling of 21113131 in words is "twenty-one million, one hundred thirteen thousand, one hundred thirty-one".