16907020721 has 2 divisors, whose sum is σ = 16907020722. Its totient is φ = 16907020720.

The previous prime is 16907020717. The next prime is 16907020769. The reversal of 16907020721 is 12702070961.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16367620096 + 539400625 = 127936^2 + 23225^2 .

It is an emirp because it is prime and its reverse (12702070961) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 16907020721 - 2² = 16907020717 is a prime.

It is not a weakly prime, because it can be changed into another prime (16907020771) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8453510360 + 8453510361.

It is an arithmetic number, because the mean of its divisors is an integer number (8453510361).

Almost surely, 2^16907020721 is an apocalyptic number.

It is an amenable number.

16907020721 is a deficient number, since it is larger than the sum of its proper divisors (1).

16907020721 is an equidigital number, since it uses as much as digits as its factorization.

16907020721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10584, while the sum is 35.

The spelling of 16907020721 in words is "sixteen billion, nine hundred seven million, twenty thousand, seven hundred twenty-one".