1638420642 has 32 divisors (see below), whose sum is σ = 3645950400. Its totient is φ = 545387904.

The previous prime is 1638420629. The next prime is 1638420659. The reversal of 1638420642 is 2460248361.

1638420642 is a `hidden beast` number, since 1 + 6 + 3 + 8 + 4 + 2 + 0 + 642 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 1638420597 and 1638420606.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19378 + ... + 60434.

It is an arithmetic number, because the mean of its divisors is an integer number (113935950).

Almost surely, 2^1638420642 is an apocalyptic number.

1638420642 is an abundant number, since it is smaller than the sum of its proper divisors (2007529758).

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

1638420642 is a wasteful number, since it uses less digits than its factorization.

1638420642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41807 (or 41801 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 36.

The square root of 1638420642 is about 40477.4090326938. The cubic root of 1638420642 is about 1178.8950304411.

The spelling of 1638420642 in words is "one billion, six hundred thirty-eight million, four hundred twenty thousand, six hundred forty-two".