28734639691 has 24 divisors (see below), whose sum is σ = 31550404736. Its totient is φ = 26137589760.

The previous prime is 28734639643. The next prime is 28734639697. The reversal of 28734639691 is 19693643782.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-28734639691 is a prime.

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28734639697) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8930515 + ... + 8933731.

Almost surely, 2^28734639691 is an apocalyptic number.

28734639691 is a deficient number, since it is larger than the sum of its proper divisors (2815765045).

28734639691 is a wasteful number, since it uses less digits than its factorization.

28734639691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4279 (or 4262 counting only the distinct ones).

The product of its digits is 11757312, while the sum is 58.

The spelling of 28734639691 in words is "twenty-eight billion, seven hundred thirty-four million, six hundred thirty-nine thousand, six hundred ninety-one".