21793251 has 8 divisors (see below), whose sum is σ = 29151760. Its totient is φ = 14481792.

The previous prime is 21793241. The next prime is 21793253. The reversal of 21793251 is 15239712.

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

It is not a de Polignac number, because 21793251 - 2¹³ = 21785059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21793253) 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, 10666 + ... + 12543.

It is an arithmetic number, because the mean of its divisors is an integer number (3643970).

Almost surely, 2^21793251 is an apocalyptic number.

21793251 is a deficient number, since it is larger than the sum of its proper divisors (7358509).

21793251 is a wasteful number, since it uses less digits than its factorization.

21793251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23525.

The product of its digits is 3780, while the sum is 30.

The square root of 21793251 is about 4668.3242175325. The cubic root of 21793251 is about 279.3234131937.

The spelling of 21793251 in words is "twenty-one million, seven hundred ninety-three thousand, two hundred fifty-one".