13781620 has 12 divisors (see below), whose sum is σ = 28941444. Its totient is φ = 5512640.

The previous prime is 13781591. The next prime is 13781653. The reversal of 13781620 is 2618731.

It can be written as a sum of positive squares in 2 ways, for example, as 3400336 + 10381284 = 1844^2 + 3222^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 344521 + ... + 344560.

It is an arithmetic number, because the mean of its divisors is an integer number (2411787).

Almost surely, 2^13781620 is an apocalyptic number.

13781620 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

13781620 is an abundant number, since it is smaller than the sum of its proper divisors (15159824).

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

13781620 is a wasteful number, since it uses less digits than its factorization.

13781620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 689090 (or 689088 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 28.

The square root of 13781620 is about 3712.3604350871. The cubic root of 13781620 is about 239.7544943183.

The spelling of 13781620 in words is "thirteen million, seven hundred eighty-one thousand, six hundred twenty".