212440391 has 2 divisors, whose sum is σ = 212440392. Its totient is φ = 212440390.

The previous prime is 212440373. The next prime is 212440411. The reversal of 212440391 is 193044212.

212440391 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-212440391 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 212440391.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (212440301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106220195 + 106220196.

It is an arithmetic number, because the mean of its divisors is an integer number (106220196).

Almost surely, 2^212440391 is an apocalyptic number.

212440391 is a deficient number, since it is larger than the sum of its proper divisors (1).

212440391 is an equidigital number, since it uses as much as digits as its factorization.

212440391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 212440391 is about 14575.3350218786. The cubic root of 212440391 is about 596.6857928321.

The spelling of 212440391 in words is "two hundred twelve million, four hundred forty thousand, three hundred ninety-one".