13400781 has 16 divisors (see below), whose sum is σ = 18448128. Its totient is φ = 8648000.

The previous prime is 13400767. The next prime is 13400801. The reversal of 13400781 is 18700431.

It is not a de Polignac number, because 13400781 - 2¹¹ = 13398733 is a prime.

It is a super-2 number, since 2×13400781² = 359161862819922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13400741) 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, 13771 + ... + 14711.

It is an arithmetic number, because the mean of its divisors is an integer number (1153008).

Almost surely, 2^13400781 is an apocalyptic number.

It is an amenable number.

13400781 is a deficient number, since it is larger than the sum of its proper divisors (5047347).

13400781 is a wasteful number, since it uses less digits than its factorization.

13400781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1092.

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 13400781 is about 3660.7077184610. The cubic root of 13400781 is about 237.5253882370.

The spelling of 13400781 in words is "thirteen million, four hundred thousand, seven hundred eighty-one".