1516221251 has 4 divisors (see below), whose sum is σ = 1517071512. Its totient is φ = 1515370992.

The previous prime is 1516221241. The next prime is 1516221281. The reversal of 1516221251 is 1521226151.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1516221251 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1516221251.

It is not an unprimeable number, because it can be changed into a prime (1516221241) 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, 422450 + ... + 426023.

It is an arithmetic number, because the mean of its divisors is an integer number (379267878).

Almost surely, 2^1516221251 is an apocalyptic number.

1516221251 is a deficient number, since it is larger than the sum of its proper divisors (850261).

1516221251 is an equidigital number, since it uses as much as digits as its factorization.

1516221251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 850260.

The product of its digits is 1200, while the sum is 26.

The square root of 1516221251 is about 38938.6857893278. The cubic root of 1516221251 is about 1148.8258339563.

The spelling of 1516221251 in words is "one billion, five hundred sixteen million, two hundred twenty-one thousand, two hundred fifty-one".