42172531 has 2 divisors, whose sum is σ = 42172532. Its totient is φ = 42172530.

The previous prime is 42172523. The next prime is 42172541. The reversal of 42172531 is 13527124.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 42172531 - 2³ = 42172523 is a prime.

It is a super-2 number, since 2×42172531² = 3557044741891922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 42172496 and 42172505.

It is not a weakly prime, because it can be changed into another prime (42172511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21086265 + 21086266.

It is an arithmetic number, because the mean of its divisors is an integer number (21086266).

Almost surely, 2^42172531 is an apocalyptic number.

42172531 is a deficient number, since it is larger than the sum of its proper divisors (1).

42172531 is an equidigital number, since it uses as much as digits as its factorization.

42172531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1680, while the sum is 25.

The square root of 42172531 is about 6494.0381119916. The cubic root of 42172531 is about 348.0779843506.

Adding to 42172531 its reverse (13527124), we get a palindrome (55699655).

The spelling of 42172531 in words is "forty-two million, one hundred seventy-two thousand, five hundred thirty-one".