21151131 has 8 divisors (see below), whose sum is σ = 28286544. Its totient is φ = 14058240.

The previous prime is 21151069. The next prime is 21151147. The reversal of 21151131 is 13115112.

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

It is not a de Polignac number, because 21151131 - 2¹¹ = 21149083 is a prime.

It is a super-2 number, since 2×21151131² = 894740685158322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21151131.

It is not an unprimeable number, because it can be changed into a prime (21151171) 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, 9450 + ... + 11471.

It is an arithmetic number, because the mean of its divisors is an integer number (3535818).

Almost surely, 2^21151131 is an apocalyptic number.

21151131 is a deficient number, since it is larger than the sum of its proper divisors (7135413).

21151131 is a wasteful number, since it uses less digits than its factorization.

21151131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21261.

The product of its digits is 30, while the sum is 15.

The square root of 21151131 is about 4599.0358772247. The cubic root of 21151131 is about 276.5526758999.

Adding to 21151131 its reverse (13115112), we get a palindrome (34266243).

The spelling of 21151131 in words is "twenty-one million, one hundred fifty-one thousand, one hundred thirty-one".