21610451 has 4 divisors (see below), whose sum is σ = 22881672. Its totient is φ = 20339232.

The previous prime is 21610439. The next prime is 21610453. The reversal of 21610451 is 15401612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21610451 - 2⁶ = 21610387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21610453) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 635585 + ... + 635618.

It is an arithmetic number, because the mean of its divisors is an integer number (5720418).

Almost surely, 2^21610451 is an apocalyptic number.

21610451 is a deficient number, since it is larger than the sum of its proper divisors (1271221).

21610451 is a wasteful number, since it uses less digits than its factorization.

21610451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1271220.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 21610451 is about 4648.7042280618. The cubic root of 21610451 is about 278.5402387421.

The spelling of 21610451 in words is "twenty-one million, six hundred ten thousand, four hundred fifty-one".