42005251 has 4 divisors (see below), whose sum is σ = 42021400. Its totient is φ = 41989104.

The previous prime is 42005237. The next prime is 42005269. The reversal of 42005251 is 15250024.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-42005251 is a prime.

It is a super-2 number, since 2×42005251² = 3528882223146002, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (42009251) 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, 3186 + ... + 9703.

It is an arithmetic number, because the mean of its divisors is an integer number (10505350).

Almost surely, 2^42005251 is an apocalyptic number.

42005251 is a deficient number, since it is larger than the sum of its proper divisors (16149).

42005251 is a wasteful number, since it uses less digits than its factorization.

42005251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16148.

The product of its (nonzero) digits is 400, while the sum is 19.

The square root of 42005251 is about 6481.1458091915. The cubic root of 42005251 is about 347.6171500881.

Adding to 42005251 its reverse (15250024), we get a palindrome (57255275).

The spelling of 42005251 in words is "forty-two million, five thousand, two hundred fifty-one".