21613233 has 8 divisors (see below), whose sum is σ = 28895200. Its totient is φ = 14370048.

The previous prime is 21613213. The next prime is 21613237. The reversal of 21613233 is 33231612.

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

It is not a de Polignac number, because 21613233 - 2⁸ = 21612977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21613237) 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, 8368 + ... + 10641.

It is an arithmetic number, because the mean of its divisors is an integer number (3611900).

Almost surely, 2^21613233 is an apocalyptic number.

It is an amenable number.

21613233 is a deficient number, since it is larger than the sum of its proper divisors (7281967).

21613233 is a wasteful number, since it uses less digits than its factorization.

21613233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19391.

The product of its digits is 648, while the sum is 21.

The square root of 21613233 is about 4649.0034415991. The cubic root of 21613233 is about 278.5521907632.

Adding to 21613233 its reverse (33231612), we get a palindrome (54844845).

The spelling of 21613233 in words is "twenty-one million, six hundred thirteen thousand, two hundred thirty-three".