638535072 has 72 divisors (see below), whose sum is σ = 1949826816. Its totient is φ = 182437248.

The previous prime is 638535067. The next prime is 638535077. The reversal of 638535072 is 270535836.

It is an interprime number because it is at equal distance from previous prime (638535067) and next prime (638535077).

It is a self number, because there is not a number n which added to its sum of digits gives 638535072.

It is not an unprimeable number, because it can be changed into a prime (638535077) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 63168 + ... + 72575.

It is an arithmetic number, because the mean of its divisors is an integer number (27080928).

Almost surely, 2^638535072 is an apocalyptic number.

It is an amenable number.

638535072 is an abundant number, since it is smaller than the sum of its proper divisors (1311291744).

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

638535072 is a wasteful number, since it uses less digits than its factorization.

638535072 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 135770 (or 135755 counting only the distinct ones).

The product of its (nonzero) digits is 151200, while the sum is 39.

The square root of 638535072 is about 25269.2515124608. The cubic root of 638535072 is about 861.1158545932.

The spelling of 638535072 in words is "six hundred thirty-eight million, five hundred thirty-five thousand, seventy-two".