42090251 has 4 divisors (see below), whose sum is σ = 48103152. Its totient is φ = 36077352.

The previous prime is 42090247. The next prime is 42090259. The reversal of 42090251 is 15209024.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 42090251 - 2² = 42090247 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42090259) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3006440 + ... + 3006453.

It is an arithmetic number, because the mean of its divisors is an integer number (12025788).

Almost surely, 2^42090251 is an apocalyptic number.

42090251 is a deficient number, since it is larger than the sum of its proper divisors (6012901).

42090251 is an equidigital number, since it uses as much as digits as its factorization.

42090251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6012900.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 42090251 is about 6487.6999776500. The cubic root of 42090251 is about 347.8514664264.

Adding to 42090251 its reverse (15209024), we get a palindrome (57299275).

The spelling of 42090251 in words is "forty-two million, ninety thousand, two hundred fifty-one".