42120391 has 2 divisors, whose sum is σ = 42120392. Its totient is φ = 42120390.

The previous prime is 42120389. The next prime is 42120409. The reversal of 42120391 is 19302124.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 42120391 - 2¹ = 42120389 is a prime.

Together with 42120389, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42120301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21060195 + 21060196.

It is an arithmetic number, because the mean of its divisors is an integer number (21060196).

Almost surely, 2^42120391 is an apocalyptic number.

42120391 is a deficient number, since it is larger than the sum of its proper divisors (1).

42120391 is an equidigital number, since it uses as much as digits as its factorization.

42120391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 42120391 is about 6490.0224190676. The cubic root of 42120391 is about 347.9344764776.

The spelling of 42120391 in words is "forty-two million, one hundred twenty thousand, three hundred ninety-one".