1640038638 has 16 divisors (see below), whose sum is σ = 3748659840. Its totient is φ = 468582456.

The previous prime is 1640038627. The next prime is 1640038661. The reversal of 1640038638 is 8368300461.

It is a junction number, because it is equal to n+sod(n) for n = 1640038596 and 1640038605.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 19524228 + ... + 19524311.

It is an arithmetic number, because the mean of its divisors is an integer number (234291240).

Almost surely, 2^1640038638 is an apocalyptic number.

1640038638 is an abundant number, since it is smaller than the sum of its proper divisors (2108621202).

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

1640038638 is a wasteful number, since it uses less digits than its factorization.

1640038638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39048551.

The product of its (nonzero) digits is 82944, while the sum is 39.

The square root of 1640038638 is about 40497.3905085254. The cubic root of 1640038638 is about 1179.2829690550.

The spelling of 1640038638 in words is "one billion, six hundred forty million, thirty-eight thousand, six hundred thirty-eight".