15720971251 has 4 divisors (see below), whose sum is σ = 15755985000. Its totient is φ = 15685957504.

The previous prime is 15720971249. The next prime is 15720971261. The reversal of 15720971251 is 15217902751.

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 15720971251 - 2¹ = 15720971249 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15720971261) 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, 17506201 + ... + 17507098.

It is an arithmetic number, because the mean of its divisors is an integer number (3938996250).

Almost surely, 2^15720971251 is an apocalyptic number.

15720971251 is a deficient number, since it is larger than the sum of its proper divisors (35013749).

15720971251 is an equidigital number, since it uses as much as digits as its factorization.

15720971251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35013748.

The product of its (nonzero) digits is 44100, while the sum is 40.

The spelling of 15720971251 in words is "fifteen billion, seven hundred twenty million, nine hundred seventy-one thousand, two hundred fifty-one".