421991939 has 2 divisors, whose sum is σ = 421991940. Its totient is φ = 421991938.

The previous prime is 421991891. The next prime is 421991951. The reversal of 421991939 is 939199124.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 421991939 - 2⁸ = 421991683 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 421991893 and 421991902.

It is not a weakly prime, because it can be changed into another prime (421994939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 210995969 + 210995970.

It is an arithmetic number, because the mean of its divisors is an integer number (210995970).

Almost surely, 2^421991939 is an apocalyptic number.

421991939 is a deficient number, since it is larger than the sum of its proper divisors (1).

421991939 is an equidigital number, since it uses as much as digits as its factorization.

421991939 is an evil number, because the sum of its binary digits is even.

The product of its digits is 157464, while the sum is 47.

The square root of 421991939 is about 20542.4423815670. The cubic root of 421991939 is about 750.0692907834.

The spelling of 421991939 in words is "four hundred twenty-one million, nine hundred ninety-one thousand, nine hundred thirty-nine".