1616690521 has 4 divisors (see below), whose sum is σ = 1672438500. Its totient is φ = 1560942544.

The previous prime is 1616690473. The next prime is 1616690567. The reversal of 1616690521 is 1250966161.

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 941262400 + 675428121 = 30680^2 + 25989^2 .

It is a cyclic number.

It is not a de Polignac number, because 1616690521 - 2²⁵ = 1583136089 is a prime.

It is a super-2 number, since 2×1616690521² = 5227376481382502882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1616690591) 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, 27873946 + ... + 27874003.

It is an arithmetic number, because the mean of its divisors is an integer number (418109625).

Almost surely, 2^1616690521 is an apocalyptic number.

It is an amenable number.

1616690521 is a deficient number, since it is larger than the sum of its proper divisors (55747979).

1616690521 is an equidigital number, since it uses as much as digits as its factorization.

1616690521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55747978.

The product of its (nonzero) digits is 19440, while the sum is 37.

The square root of 1616690521 is about 40208.0902431339. The cubic root of 1616690521 is about 1173.6599834035.

The spelling of 1616690521 in words is "one billion, six hundred sixteen million, six hundred ninety thousand, five hundred twenty-one".