721705021077 has 4 divisors (see below), whose sum is σ = 962273361440. Its totient is φ = 481136680716.

The previous prime is 721705021031. The next prime is 721705021097. The reversal of 721705021077 is 770120507127.

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 not a de Polignac number, because 721705021077 - 2⁸ = 721705020821 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721705021097) 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, 120284170177 + ... + 120284170182.

It is an arithmetic number, because the mean of its divisors is an integer number (240568340360).

Almost surely, 2^721705021077 is an apocalyptic number.

It is an amenable number.

721705021077 is a deficient number, since it is larger than the sum of its proper divisors (240568340363).

721705021077 is a wasteful number, since it uses less digits than its factorization.

721705021077 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240568340362.

The product of its (nonzero) digits is 48020, while the sum is 39.

The spelling of 721705021077 in words is "seven hundred twenty-one billion, seven hundred five million, twenty-one thousand, seventy-seven".