29996891921 has 4 divisors (see below), whose sum is σ = 30635123712. Its totient is φ = 29358660132.

The previous prime is 29996891879. The next prime is 29996891927. The reversal of 29996891921 is 12919869992.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 29996891921 - 2⁶ = 29996891857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (29996891927) 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, 319115825 + ... + 319115918.

It is an arithmetic number, because the mean of its divisors is an integer number (7658780928).

Almost surely, 2^29996891921 is an apocalyptic number.

It is an amenable number.

29996891921 is a deficient number, since it is larger than the sum of its proper divisors (638231791).

29996891921 is an equidigital number, since it uses as much as digits as its factorization.

29996891921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 638231790.

The product of its digits is 11337408, while the sum is 65.

The spelling of 29996891921 in words is "twenty-nine billion, nine hundred ninety-six million, eight hundred ninety-one thousand, nine hundred twenty-one".