1640869460 has 24 divisors (see below), whose sum is σ = 3481353960. Its totient is φ = 649580544.

The previous prime is 1640869423. The next prime is 1640869471. The reversal of 1640869460 is 649680461.

It can be written as a sum of positive squares in 4 ways, for example, as 781456 + 1640088004 = 884^2 + 40498^2 .

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, 420965 + ... + 424844.

It is an arithmetic number, because the mean of its divisors is an integer number (145056415).

Almost surely, 2^1640869460 is an apocalyptic number.

1640869460 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1640869460 is an abundant number, since it is smaller than the sum of its proper divisors (1840484500).

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

1640869460 is a wasteful number, since it uses less digits than its factorization.

1640869460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 845915 (or 845913 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 44.

The square root of 1640869460 is about 40507.6469324003. The cubic root of 1640869460 is about 1179.4820718509.

The spelling of 1640869460 in words is "one billion, six hundred forty million, eight hundred sixty-nine thousand, four hundred sixty".