13781640 has 32 divisors (see below), whose sum is σ = 41345280. Its totient is φ = 3675072.

The previous prime is 13781591. The next prime is 13781653. The reversal of 13781640 is 4618731.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 13781598 and 13781607.

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, 57304 + ... + 57543.

It is an arithmetic number, because the mean of its divisors is an integer number (1292040).

Almost surely, 2^13781640 is an apocalyptic number.

13781640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

13781640 is an abundant number, since it is smaller than the sum of its proper divisors (27563640).

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

13781640 is a wasteful number, since it uses less digits than its factorization.

13781640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114861 (or 114857 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 30.

The square root of 13781640 is about 3712.3631287901. The cubic root of 13781640 is about 239.7546102962.

The spelling of 13781640 in words is "thirteen million, seven hundred eighty-one thousand, six hundred forty".