42815989 has 2 divisors, whose sum is σ = 42815990. Its totient is φ = 42815988.

The previous prime is 42815957. The next prime is 42815999. The reversal of 42815989 is 98951824.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 42797764 + 18225 = 6542^2 + 135^2 .

It is a cyclic number.

It is not a de Polignac number, because 42815989 - 2⁵ = 42815957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (42815939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 21407994 + 21407995.

It is an arithmetic number, because the mean of its divisors is an integer number (21407995).

Almost surely, 2^42815989 is an apocalyptic number.

It is an amenable number.

42815989 is a deficient number, since it is larger than the sum of its proper divisors (1).

42815989 is an equidigital number, since it uses as much as digits as its factorization.

42815989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 207360, while the sum is 46.

The square root of 42815989 is about 6543.3927743946. The cubic root of 42815989 is about 349.8393521252.

The spelling of 42815989 in words is "forty-two million, eight hundred fifteen thousand, nine hundred eighty-nine".