1634561640 has 128 divisors (see below), whose sum is σ = 5735376000. Its totient is φ = 412936704.

The previous prime is 1634561633. The next prime is 1634561641. The reversal of 1634561640 is 461654361.

It is a happy number.

1634561640 is a `hidden beast` number, since 1 + 6 + 3 + 4 + 5 + 6 + 1 + 640 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1634561595 and 1634561604.

It is not an unprimeable number, because it can be changed into a prime (1634561641) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 19309 + ... + 60348.

It is an arithmetic number, because the mean of its divisors is an integer number (44807625).

Almost surely, 2^1634561640 is an apocalyptic number.

1634561640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1634561640 is an abundant number, since it is smaller than the sum of its proper divisors (4100814360).

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

1634561640 is a wasteful number, since it uses less digits than its factorization.

1634561640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79696 (or 79686 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 1634561640 is about 40429.7123412967. The cubic root of 1634561640 is about 1177.9687451773.

The spelling of 1634561640 in words is "one billion, six hundred thirty-four million, five hundred sixty-one thousand, six hundred forty".