13990781 has 16 divisors (see below), whose sum is σ = 16689024. Its totient is φ = 11479104.

The previous prime is 13990751. The next prime is 13990793. The reversal of 13990781 is 18709931.

It is not a de Polignac number, because 13990781 - 2²² = 9796477 is a prime.

It is a super-2 number, since 2×13990781² = 391483905979922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13990721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15515 + ... + 16391.

It is an arithmetic number, because the mean of its divisors is an integer number (1043064).

Almost surely, 2^13990781 is an apocalyptic number.

It is an amenable number.

13990781 is a deficient number, since it is larger than the sum of its proper divisors (2698243).

13990781 is an equidigital number, since it uses as much as digits as its factorization.

13990781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 980.

The product of its (nonzero) digits is 13608, while the sum is 38.

The square root of 13990781 is about 3740.4252432043. The cubic root of 13990781 is about 240.9613121784.

The spelling of 13990781 in words is "thirteen million, nine hundred ninety thousand, seven hundred eighty-one".