42209978 has 4 divisors (see below), whose sum is σ = 63314970. Its totient is φ = 21104988.

The previous prime is 42209977. The next prime is 42209983. The reversal of 42209978 is 87990224.

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

It can be written as a sum of positive squares in only one way, i.e., 41899729 + 310249 = 6473^2 + 557^2 .

It is not an unprimeable number, because it can be changed into a prime (42209971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10552493 + ... + 10552496.

Almost surely, 2^42209978 is an apocalyptic number.

42209978 is a deficient number, since it is larger than the sum of its proper divisors (21104992).

42209978 is a wasteful number, since it uses less digits than its factorization.

42209978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21104991.

The product of its (nonzero) digits is 72576, while the sum is 41.

The square root of 42209978 is about 6496.9206552027. The cubic root of 42209978 is about 348.1809788820.

The spelling of 42209978 in words is "forty-two million, two hundred nine thousand, nine hundred seventy-eight".