722431021 has 4 divisors (see below), whose sum is σ = 778002652. Its totient is φ = 666859392.

The previous prime is 722431013. The next prime is 722431027. The reversal of 722431021 is 120134227.

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 364275396 + 358155625 = 19086^2 + 18925^2 .

It is a cyclic number.

It is not a de Polignac number, because 722431021 - 2³ = 722431013 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 722430983 and 722431001.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (722431027) 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, 27785796 + ... + 27785821.

It is an arithmetic number, because the mean of its divisors is an integer number (194500663).

Almost surely, 2^722431021 is an apocalyptic number.

It is an amenable number.

722431021 is a deficient number, since it is larger than the sum of its proper divisors (55571631).

722431021 is a wasteful number, since it uses less digits than its factorization.

722431021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55571630.

The product of its (nonzero) digits is 672, while the sum is 22.

The square root of 722431021 is about 26878.0769587409. The cubic root of 722431021 is about 897.2885558539.

Adding to 722431021 its reverse (120134227), we get a palindrome (842565248).

The spelling of 722431021 in words is "seven hundred twenty-two million, four hundred thirty-one thousand, twenty-one".