1631555540 has 24 divisors (see below), whose sum is σ = 3440493672. Its totient is φ = 649912320.

The previous prime is 1631555533. The next prime is 1631555543. The reversal of 1631555540 is 455551361.

It can be written as a sum of positive squares in 4 ways, for example, as 63712324 + 1567843216 = 7982^2 + 39596^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1631555540.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1631555543) 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, 164429 + ... + 174068.

It is an arithmetic number, because the mean of its divisors is an integer number (143353903).

Almost surely, 2^1631555540 is an apocalyptic number.

1631555540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1631555540 is an abundant number, since it is smaller than the sum of its proper divisors (1808938132).

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

1631555540 is a wasteful number, since it uses less digits than its factorization.

1631555540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 338747 (or 338745 counting only the distinct ones).

The product of its (nonzero) digits is 45000, while the sum is 35.

The square root of 1631555540 is about 40392.5183666480. The cubic root of 1631555540 is about 1177.2461732922.

The spelling of 1631555540 in words is "one billion, six hundred thirty-one million, five hundred fifty-five thousand, five hundred forty".