21154331 has 8 divisors (see below), whose sum is σ = 23113728. Its totient is φ = 19201000.

The previous prime is 21154283. The next prime is 21154339. The reversal of 21154331 is 13345112.

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-21154331 is a prime.

It is a super-2 number, since 2×21154331² = 895011440115122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21154339) 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 7 ways as a sum of consecutive naturals, for example, 8966 + ... + 11076.

It is an arithmetic number, because the mean of its divisors is an integer number (2889216).

Almost surely, 2^21154331 is an apocalyptic number.

21154331 is a deficient number, since it is larger than the sum of its proper divisors (1959397).

21154331 is a wasteful number, since it uses less digits than its factorization.

21154331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3033.

The product of its digits is 360, while the sum is 20.

The square root of 21154331 is about 4599.3837630709. The cubic root of 21154331 is about 276.5666219459.

Adding to 21154331 its reverse (13345112), we get a palindrome (34499443).

It can be divided in two parts, 2115 and 4331, that added together give a palindrome (6446).

The spelling of 21154331 in words is "twenty-one million, one hundred fifty-four thousand, three hundred thirty-one".