639630154 has 4 divisors (see below), whose sum is σ = 959445234. Its totient is φ = 319815076.

The previous prime is 639630149. The next prime is 639630157. The reversal of 639630154 is 451036936.

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., 469718929 + 169911225 = 21673^2 + 13035^2 .

It is not an unprimeable number, because it can be changed into a prime (639630157) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 159907537 + ... + 159907540.

Almost surely, 2^639630154 is an apocalyptic number.

639630154 is a deficient number, since it is larger than the sum of its proper divisors (319815080).

639630154 is a wasteful number, since it uses less digits than its factorization.

639630154 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319815079.

The product of its (nonzero) digits is 58320, while the sum is 37.

The square root of 639630154 is about 25290.9105016012. The cubic root of 639630154 is about 861.6078421399.

The spelling of 639630154 in words is "six hundred thirty-nine million, six hundred thirty thousand, one hundred fifty-four".