672720691 has 2 divisors, whose sum is σ = 672720692. Its totient is φ = 672720690.

The previous prime is 672720673. The next prime is 672720757. The reversal of 672720691 is 196027276.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 672720691 - 2⁷ = 672720563 is a prime.

It is not a weakly prime, because it can be changed into another prime (672721691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 336360345 + 336360346.

It is an arithmetic number, because the mean of its divisors is an integer number (336360346).

Almost surely, 2^672720691 is an apocalyptic number.

672720691 is a deficient number, since it is larger than the sum of its proper divisors (1).

672720691 is an equidigital number, since it uses as much as digits as its factorization.

672720691 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 63504, while the sum is 40.

The square root of 672720691 is about 25936.8596981207. The cubic root of 672720691 is about 876.2168391259.

The spelling of 672720691 in words is "six hundred seventy-two million, seven hundred twenty thousand, six hundred ninety-one".