616918981 has 4 divisors (see below), whose sum is σ = 705050272. Its totient is φ = 528787692.

The previous prime is 616918957. The next prime is 616919021. The reversal of 616918981 is 189819616.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 616918981 - 2⁷ = 616918853 is a prime.

It is a super-2 number, since 2×616918981² = 761178058236156722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (616912981) 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, 44065635 + ... + 44065648.

It is an arithmetic number, because the mean of its divisors is an integer number (176262568).

Almost surely, 2^616918981 is an apocalyptic number.

It is an amenable number.

616918981 is a deficient number, since it is larger than the sum of its proper divisors (88131291).

616918981 is an equidigital number, since it uses as much as digits as its factorization.

616918981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 88131290.

The product of its digits is 186624, while the sum is 49.

The square root of 616918981 is about 24837.8537921456. The cubic root of 616918981 is about 851.2870840025.

The spelling of 616918981 in words is "six hundred sixteen million, nine hundred eighteen thousand, nine hundred eighty-one".