1616636991 has 4 divisors (see below), whose sum is σ = 2155515992. Its totient is φ = 1077757992.

The previous prime is 1616636977. The next prime is 1616637019. The reversal of 1616636991 is 1996366161.

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

It is not a de Polignac number, because 1616636991 - 2⁶ = 1616636927 is a prime.

It is a super-2 number, since 2×1616636991² = 5227030321339068162, which contains 22 as substring.

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 1616636991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1616636951) 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, 269439496 + ... + 269439501.

It is an arithmetic number, because the mean of its divisors is an integer number (538878998).

Almost surely, 2^1616636991 is an apocalyptic number.

1616636991 is a deficient number, since it is larger than the sum of its proper divisors (538879001).

1616636991 is an equidigital number, since it uses as much as digits as its factorization.

1616636991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 538879000.

The product of its digits is 314928, while the sum is 48.

The square root of 1616636991 is about 40207.4245755681. The cubic root of 1616636991 is about 1173.6470296333.

The spelling of 1616636991 in words is "one billion, six hundred sixteen million, six hundred thirty-six thousand, nine hundred ninety-one".