1516556991 has 8 divisors (see below), whose sum is σ = 2128501120. Its totient is φ = 957825432.

The previous prime is 1516556971. The next prime is 1516557017. The reversal of 1516556991 is 1996556151.

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

It is not a de Polignac number, because 1516556991 - 2⁵ = 1516556959 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 1516556991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1516556941) 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, 13303075 + ... + 13303188.

It is an arithmetic number, because the mean of its divisors is an integer number (266062640).

Almost surely, 2^1516556991 is an apocalyptic number.

1516556991 is a deficient number, since it is larger than the sum of its proper divisors (611944129).

1516556991 is a wasteful number, since it uses less digits than its factorization.

1516556991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26606285.

The product of its digits is 364500, while the sum is 48.

The square root of 1516556991 is about 38942.9966874662. The cubic root of 1516556991 is about 1148.9106233231.

The spelling of 1516556991 in words is "one billion, five hundred sixteen million, five hundred fifty-six thousand, nine hundred ninety-one".