616591993 has 4 divisors (see below), whose sum is σ = 619150708. Its totient is φ = 614033280.

The previous prime is 616591957. The next prime is 616592017. The reversal of 616591993 is 399195616.

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

It can be written as a sum of positive squares in 2 ways, for example, as 472279824 + 144312169 = 21732^2 + 12013^2 .

It is a cyclic number.

It is not a de Polignac number, because 616591993 - 2²⁵ = 583037561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (616591693) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1278996 + ... + 1279477.

It is an arithmetic number, because the mean of its divisors is an integer number (154787677).

Almost surely, 2^616591993 is an apocalyptic number.

It is an amenable number.

616591993 is a deficient number, since it is larger than the sum of its proper divisors (2558715).

616591993 is a wasteful number, since it uses less digits than its factorization.

616591993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2558714.

The product of its digits is 393660, while the sum is 49.

The square root of 616591993 is about 24831.2704668932. The cubic root of 616591993 is about 851.1366537384.

The spelling of 616591993 in words is "six hundred sixteen million, five hundred ninety-one thousand, nine hundred ninety-three".