13781961 has 16 divisors (see below), whose sum is σ = 20805120. Its totient is φ = 9013680.

The previous prime is 13781959. The next prime is 13781983. The reversal of 13781961 is 16918731.

13781961 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 13781961 - 2¹ = 13781959 is a prime.

It is a super-3 number, since 3×13781961³ (a number of 22 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (13781941) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3385 + ... + 6246.

It is an arithmetic number, because the mean of its divisors is an integer number (1300320).

Almost surely, 2^13781961 is an apocalyptic number.

It is an amenable number.

13781961 is a deficient number, since it is larger than the sum of its proper divisors (7023159).

13781961 is an equidigital number, since it uses as much as digits as its factorization.

13781961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9693 (or 9687 counting only the distinct ones).

The product of its digits is 9072, while the sum is 36.

The square root of 13781961 is about 3712.4063624555. The cubic root of 13781961 is about 239.7564717252.

The spelling of 13781961 in words is "thirteen million, seven hundred eighty-one thousand, nine hundred sixty-one".