638817420 has 48 divisors (see below), whose sum is σ = 1826754048. Its totient is φ = 166726080.

The previous prime is 638817419. The next prime is 638817497. The reversal of 638817420 is 24718836.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 110446 + ... + 116085.

It is an arithmetic number, because the mean of its divisors is an integer number (38057376).

Almost surely, 2^638817420 is an apocalyptic number.

638817420 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

638817420 is an abundant number, since it is smaller than the sum of its proper divisors (1187936628).

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

638817420 is a wasteful number, since it uses less digits than its factorization.

638817420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226590 (or 226588 counting only the distinct ones).

The product of its (nonzero) digits is 64512, while the sum is 39.

The square root of 638817420 is about 25274.8376849388. The cubic root of 638817420 is about 861.2427588789.

The spelling of 638817420 in words is "six hundred thirty-eight million, eight hundred seventeen thousand, four hundred twenty".