42978637 has 4 divisors (see below), whose sum is σ = 46284700. Its totient is φ = 39672576.

The previous prime is 42978623. The next prime is 42978659. The reversal of 42978637 is 73687924.

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

It can be written as a sum of positive squares in 2 ways, for example, as 23872996 + 19105641 = 4886^2 + 4371^2 .

It is a cyclic number.

It is not a de Polignac number, because 42978637 - 2¹⁵ = 42945869 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (42978037) 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, 1653012 + ... + 1653037.

It is an arithmetic number, because the mean of its divisors is an integer number (11571175).

Almost surely, 2^42978637 is an apocalyptic number.

It is an amenable number.

42978637 is a deficient number, since it is larger than the sum of its proper divisors (3306063).

42978637 is a wasteful number, since it uses less digits than its factorization.

42978637 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3306062.

The product of its digits is 508032, while the sum is 46.

The square root of 42978637 is about 6555.8094084560. The cubic root of 42978637 is about 350.2817785266.

The spelling of 42978637 in words is "forty-two million, nine hundred seventy-eight thousand, six hundred thirty-seven".