1616867376721 has 3 divisors (see below), whose sum is σ = 1616868648283. Its totient is φ = 1616866105160.

The previous prime is 1616867376703. The next prime is 1616867376727. The reversal of 1616867376721 is 1276737686161.

The square root of 1616867376721 is 1271561.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 1530760343121 + 86107033600 = 1237239^2 + 293440^2 .

It is not a de Polignac number, because 1616867376721 - 2⁹ = 1616867376209 is a prime.

It is a super-2 number, since 2×1616867376721² (a number of 25 digits) 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 1616867376721.

It is not an unprimeable number, because it can be changed into a prime (1616867376727) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 635781 + ... + 1907341.

Almost surely, 2^{1616867376721} is an apocalyptic number.

1616867376721 is the 1271561-st square number.

1616867376721 is the 635781-st centered octagonal number.

It is an amenable number.

1616867376721 is a deficient number, since it is larger than the sum of its proper divisors (1271562).

1616867376721 is an frugal number, since it uses more digits than its factorization.

1616867376721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2543122 (or 1271561 counting only the distinct ones).

The product of its digits is 21337344, while the sum is 61.

The spelling of 1616867376721 in words is "one trillion, six hundred sixteen billion, eight hundred sixty-seven million, three hundred seventy-six thousand, seven hundred twenty-one".