21120791251 has 8 divisors (see below), whose sum is σ = 24140622944. Its totient is φ = 18101603520.

The previous prime is 21120791231. The next prime is 21120791287. The reversal of 21120791251 is 15219702112.

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

It is not a de Polignac number, because 21120791251 - 2¹¹ = 21120789203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21120791201) 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, 88530 + ... + 223783.

It is an arithmetic number, because the mean of its divisors is an integer number (3017577868).

Almost surely, 2^21120791251 is an apocalyptic number.

21120791251 is a deficient number, since it is larger than the sum of its proper divisors (3019831693).

21120791251 is an equidigital number, since it uses as much as digits as its factorization.

21120791251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321981.

The product of its (nonzero) digits is 2520, while the sum is 31.

The spelling of 21120791251 in words is "twenty-one billion, one hundred twenty million, seven hundred ninety-one thousand, two hundred fifty-one".