39399821 has 2 divisors, whose sum is σ = 39399822. Its totient is φ = 39399820.

The previous prime is 39399799. The next prime is 39399847. The reversal of 39399821 is 12899393.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 36120100 + 3279721 = 6010^2 + 1811^2 .

It is a cyclic number.

It is not a de Polignac number, because 39399821 - 2¹⁰ = 39398797 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (39399121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19699910 + 19699911.

It is an arithmetic number, because the mean of its divisors is an integer number (19699911).

Almost surely, 2^39399821 is an apocalyptic number.

It is an amenable number.

39399821 is a deficient number, since it is larger than the sum of its proper divisors (1).

39399821 is an equidigital number, since it uses as much as digits as its factorization.

39399821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 104976, while the sum is 44.

The square root of 39399821 is about 6276.9276720383. The cubic root of 39399821 is about 340.2760762298.

The spelling of 39399821 in words is "thirty-nine million, three hundred ninety-nine thousand, eight hundred twenty-one".