1640557464 has 128 divisors (see below), whose sum is σ = 5085642240. Its totient is φ = 429437952.

The previous prime is 1640557459. The next prime is 1640557483. The reversal of 1640557464 is 4647550461.

It is a super-2 number, since 2×1640557464² = 5382857585372222592, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 296467 + ... + 301949.

It is an arithmetic number, because the mean of its divisors is an integer number (39731580).

Almost surely, 2^1640557464 is an apocalyptic number.

1640557464 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1640557464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2542821120).

1640557464 is an abundant number, since it is smaller than the sum of its proper divisors (3445084776).

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

1640557464 is a wasteful number, since it uses less digits than its factorization.

1640557464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5649 (or 5645 counting only the distinct ones).

The product of its (nonzero) digits is 403200, while the sum is 42.

The square root of 1640557464 is about 40503.7956739859. The cubic root of 1640557464 is about 1179.4073112796.

The spelling of 1640557464 in words is "one billion, six hundred forty million, five hundred fifty-seven thousand, four hundred sixty-four".