1640621400 has 96 divisors (see below), whose sum is σ = 5548305600. Its totient is φ = 397724800.

The previous prime is 1640621393. The next prime is 1640621419. The reversal of 1640621400 is 41260461.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 117690 + ... + 130889.

It is an arithmetic number, because the mean of its divisors is an integer number (57794850).

Almost surely, 2^1640621400 is an apocalyptic number.

1640621400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1640621400 is an abundant number, since it is smaller than the sum of its proper divisors (3907684200).

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

1640621400 is a wasteful number, since it uses less digits than its factorization.

1640621400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248609 (or 248600 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 1640621400 is about 40504.5849256600. The cubic root of 1640621400 is about 1179.4226324145.

Adding to 1640621400 its reverse (41260461), we get a palindrome (1681881861).

The spelling of 1640621400 in words is "one billion, six hundred forty million, six hundred twenty-one thousand, four hundred".