616721555 has 8 divisors (see below), whose sum is σ = 742478352. Its totient is φ = 491768928.

The previous prime is 616721477. The next prime is 616721603. The reversal of 616721555 is 555127616.

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

It is a cyclic number.

It is not a de Polignac number, because 616721555 - 2¹⁴ = 616705171 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 199352 + ... + 202421.

It is an arithmetic number, because the mean of its divisors is an integer number (92809794).

Almost surely, 2^616721555 is an apocalyptic number.

616721555 is a deficient number, since it is larger than the sum of its proper divisors (125756797).

616721555 is a wasteful number, since it uses less digits than its factorization.

616721555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 402085.

The product of its digits is 63000, while the sum is 38.

The square root of 616721555 is about 24833.8791774463. The cubic root of 616721555 is about 851.1962648727.

The spelling of 616721555 in words is "six hundred sixteen million, seven hundred twenty-one thousand, five hundred fifty-five".