6720161691 has 4 divisors (see below), whose sum is σ = 8960215592. Its totient is φ = 4480107792.

The previous prime is 6720161687. The next prime is 6720161711. The reversal of 6720161691 is 1961610276.

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

It is not a de Polignac number, because 6720161691 - 2² = 6720161687 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6720161611) 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, 1120026946 + ... + 1120026951.

It is an arithmetic number, because the mean of its divisors is an integer number (2240053898).

Almost surely, 2^6720161691 is an apocalyptic number.

6720161691 is a deficient number, since it is larger than the sum of its proper divisors (2240053901).

6720161691 is a wasteful number, since it uses less digits than its factorization.

6720161691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2240053900.

The product of its (nonzero) digits is 27216, while the sum is 39.

The square root of 6720161691 is about 81976.5923358613. The cubic root of 6720161691 is about 1887.0927270976.

The spelling of 6720161691 in words is "six billion, seven hundred twenty million, one hundred sixty-one thousand, six hundred ninety-one".