616521637 has 2 divisors, whose sum is σ = 616521638. Its totient is φ = 616521636.

The previous prime is 616521623. The next prime is 616521667. The reversal of 616521637 is 736125616.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 512297956 + 104223681 = 22634^2 + 10209^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-616521637 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 616521596 and 616521605.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (616521667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 308260818 + 308260819.

It is an arithmetic number, because the mean of its divisors is an integer number (308260819).

Almost surely, 2^616521637 is an apocalyptic number.

It is an amenable number.

616521637 is a deficient number, since it is larger than the sum of its proper divisors (1).

616521637 is an equidigital number, since it uses as much as digits as its factorization.

616521637 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 45360, while the sum is 37.

The square root of 616521637 is about 24829.8537450385. The cubic root of 616521637 is about 851.1042796300.

The spelling of 616521637 in words is "six hundred sixteen million, five hundred twenty-one thousand, six hundred thirty-seven".