721076861 has 4 divisors (see below), whose sum is σ = 721211424. Its totient is φ = 720942300.

The previous prime is 721076857. The next prime is 721076891. The reversal of 721076861 is 168670127.

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 a cyclic number.

It is not a de Polignac number, because 721076861 - 2² = 721076857 is a prime.

It is a super-2 number, since 2×721076861² = 1039903678939226642, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721076801) 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, 58895 + ... + 70076.

It is an arithmetic number, because the mean of its divisors is an integer number (180302856).

Almost surely, 2^721076861 is an apocalyptic number.

It is an amenable number.

721076861 is a deficient number, since it is larger than the sum of its proper divisors (134563).

721076861 is a wasteful number, since it uses less digits than its factorization.

721076861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134562.

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 721076861 is about 26852.8743526647. The cubic root of 721076861 is about 896.7275646894.

The spelling of 721076861 in words is "seven hundred twenty-one million, seventy-six thousand, eight hundred sixty-one".