722021821 has 2 divisors, whose sum is σ = 722021822. Its totient is φ = 722021820.

The previous prime is 722021813. The next prime is 722021873. The reversal of 722021821 is 128120227.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 455352921 + 266668900 = 21339^2 + 16330^2 .

It is a cyclic number.

It is not a de Polignac number, because 722021821 - 2³ = 722021813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (722021891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 361010910 + 361010911.

It is an arithmetic number, because the mean of its divisors is an integer number (361010911).

Almost surely, 2^722021821 is an apocalyptic number.

It is an amenable number.

722021821 is a deficient number, since it is larger than the sum of its proper divisors (1).

722021821 is an equidigital number, since it uses as much as digits as its factorization.

722021821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 722021821 is about 26870.4637287859. The cubic root of 722021821 is about 897.1191095389.

The spelling of 722021821 in words is "seven hundred twenty-two million, twenty-one thousand, eight hundred twenty-one".