1638420641 has 16 divisors (see below), whose sum is σ = 1961184960. Its totient is φ = 1348950720.

The previous prime is 1638420629. The next prime is 1638420659. The reversal of 1638420641 is 1460248361.

It is not a de Polignac number, because 1638420641 - 2¹⁰ = 1638419617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1638420601) by changing a digit.

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, 100511 + ... + 115668.

It is an arithmetic number, because the mean of its divisors is an integer number (122574060).

Almost surely, 2^1638420641 is an apocalyptic number.

1638420641 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1638420641 is a deficient number, since it is larger than the sum of its proper divisors (322764319).

1638420641 is a wasteful number, since it uses less digits than its factorization.

1638420641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216256.

The product of its (nonzero) digits is 27648, while the sum is 35.

The square root of 1638420641 is about 40477.4090203412. The cubic root of 1638420641 is about 1178.8950302013.

The spelling of 1638420641 in words is "one billion, six hundred thirty-eight million, four hundred twenty thousand, six hundred forty-one".