6616661615 has 4 divisors (see below), whose sum is σ = 7939993944. Its totient is φ = 5293329288.

The previous prime is 6616661591. The next prime is 6616661629. The reversal of 6616661615 is 5161666166.

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

It is a cyclic number.

It is not a de Polignac number, because 6616661615 - 2¹⁶ = 6616596079 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 661666157 + ... + 661666166.

It is an arithmetic number, because the mean of its divisors is an integer number (1984998486).

Almost surely, 2^6616661615 is an apocalyptic number.

6616661615 is a deficient number, since it is larger than the sum of its proper divisors (1323332329).

6616661615 is a wasteful number, since it uses less digits than its factorization.

6616661615 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1323332328.

The product of its digits is 233280, while the sum is 44.

The square root of 6616661615 is about 81342.8645610664. The cubic root of 6616661615 is about 1877.3545876366.

It can be divided in two parts, 661666161 and 5, that added together give a palindrome (661666166).

The spelling of 6616661615 in words is "six billion, six hundred sixteen million, six hundred sixty-one thousand, six hundred fifteen".