721620701 has 4 divisors (see below), whose sum is σ = 721899900. Its totient is φ = 721341504.

The previous prime is 721620689. The next prime is 721620749. The reversal of 721620701 is 107026127.

721620701 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in 2 ways, for example, as 227225476 + 494395225 = 15074^2 + 22235^2 .

It is a cyclic number.

It is not a de Polignac number, because 721620701 - 2⁶ = 721620637 is a prime.

It is a super-2 number, since 2×721620701² = 1041472872223462802, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721620901) 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, 135686 + ... + 140903.

It is an arithmetic number, because the mean of its divisors is an integer number (180474975).

Almost surely, 2^721620701 is an apocalyptic number.

It is an amenable number.

721620701 is a deficient number, since it is larger than the sum of its proper divisors (279199).

721620701 is a wasteful number, since it uses less digits than its factorization.

721620701 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 279198.

The product of its (nonzero) digits is 1176, while the sum is 26.

The square root of 721620701 is about 26862.9987343185. The cubic root of 721620701 is about 896.9529469354.

Adding to 721620701 its reverse (107026127), we get a palindrome (828646828).

The spelling of 721620701 in words is "seven hundred twenty-one million, six hundred twenty thousand, seven hundred one".