21152431 has 8 divisors (see below), whose sum is σ = 21847760. Its totient is φ = 20466432.

The previous prime is 21152423. The next prime is 21152441. The reversal of 21152431 is 13425112.

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

It is a cyclic number.

It is not a de Polignac number, because 21152431 - 2³ = 21152423 is a prime.

It is a super-2 number, since 2×21152431² = 894850674419522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21152399 and 21152408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21152441) 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, 2431 + ... + 6943.

It is an arithmetic number, because the mean of its divisors is an integer number (2730970).

Almost surely, 2^21152431 is an apocalyptic number.

21152431 is a deficient number, since it is larger than the sum of its proper divisors (695329).

21152431 is a wasteful number, since it uses less digits than its factorization.

21152431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4665.

The product of its digits is 240, while the sum is 19.

The square root of 21152431 is about 4599.1772090234. The cubic root of 21152431 is about 276.5583416507.

Adding to 21152431 its reverse (13425112), we get a palindrome (34577543).

The spelling of 21152431 in words is "twenty-one million, one hundred fifty-two thousand, four hundred thirty-one".