4394432821 has 2 divisors, whose sum is σ = 4394432822. Its totient is φ = 4394432820.

The previous prime is 4394432789. The next prime is 4394432851. The reversal of 4394432821 is 1282344934.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4315044721 + 79388100 = 65689^2 + 8910^2 .

It is a cyclic number.

It is not a de Polignac number, because 4394432821 - 2⁵ = 4394432789 is a prime.

It is a super-2 number, since 2×4394432821² = 38622079636564036082, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4394432851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2197216410 + 2197216411.

It is an arithmetic number, because the mean of its divisors is an integer number (2197216411).

Almost surely, 2^4394432821 is an apocalyptic number.

It is an amenable number.

4394432821 is a deficient number, since it is larger than the sum of its proper divisors (1).

4394432821 is an equidigital number, since it uses as much as digits as its factorization.

4394432821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 165888, while the sum is 40.

The square root of 4394432821 is about 66290.5183340725. The cubic root of 4394432821 is about 1637.9511422188.

The spelling of 4394432821 in words is "four billion, three hundred ninety-four million, four hundred thirty-two thousand, eight hundred twenty-one".