1631640 has 32 divisors (see below), whose sum is σ = 4895280. Its totient is φ = 435072.

The previous prime is 1631639. The next prime is 1631647. The reversal of 1631640 is 461361.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1631647) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6679 + ... + 6918.

2^1631640 is an apocalyptic number.

1631640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1631640 is an abundant number, since it is smaller than the sum of its proper divisors (3263640).

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

1631640 is a wasteful number, since it uses less digits than its factorization.

1631640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13611 (or 13607 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 21.

The square root of 1631640 is about 1277.3566455771. The cubic root of 1631640 is about 117.7266486932.

The spelling of 1631640 in words is "one million, six hundred thirty-one thousand, six hundred forty".