21232491 has 8 divisors (see below), whose sum is σ = 32354304. Its totient is φ = 12132840.

The previous prime is 21232469. The next prime is 21232493. The reversal of 21232491 is 19423212.

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

It is not a de Polignac number, because 21232491 - 2⁵ = 21232459 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21232493) 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, 505515 + ... + 505556.

It is an arithmetic number, because the mean of its divisors is an integer number (4044288).

Almost surely, 2^21232491 is an apocalyptic number.

21232491 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21232491 is a deficient number, since it is larger than the sum of its proper divisors (11121813).

21232491 is a wasteful number, since it uses less digits than its factorization.

21232491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1011081.

The product of its digits is 864, while the sum is 24.

The square root of 21232491 is about 4607.8727195963. The cubic root of 21232491 is about 276.9068183059.

The spelling of 21232491 in words is "twenty-one million, two hundred thirty-two thousand, four hundred ninety-one".