642939090 has 16 divisors (see below), whose sum is σ = 1543053888. Its totient is φ = 171450416.

The previous prime is 642939041. The next prime is 642939097. The reversal of 642939090 is 90939246.

It is not an unprimeable number, because it can be changed into a prime (642939097) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10715622 + ... + 10715681.

It is an arithmetic number, because the mean of its divisors is an integer number (96440868).

Almost surely, 2^642939090 is an apocalyptic number.

642939090 is an abundant number, since it is smaller than the sum of its proper divisors (900114798).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

642939090 is a wasteful number, since it uses less digits than its factorization.

642939090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21431313.

The product of its (nonzero) digits is 104976, while the sum is 42.

The square root of 642939090 is about 25356.2436098094. The cubic root of 642939090 is about 863.0910445784.

The spelling of 642939090 in words is "six hundred forty-two million, nine hundred thirty-nine thousand, ninety".