13431781 has 16 divisors (see below), whose sum is σ = 15238080. Its totient is φ = 11733120.

The previous prime is 13431767. The next prime is 13431787. The reversal of 13431781 is 18713431.

It is a cyclic number.

It is not a de Polignac number, because 13431781 - 2¹⁹ = 12907493 is a prime.

It is a super-2 number, since 2×13431781² = 360825481663922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13431787) 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, 34335 + ... + 34723.

It is an arithmetic number, because the mean of its divisors is an integer number (952380).

Almost surely, 2^13431781 is an apocalyptic number.

13431781 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

13431781 is a deficient number, since it is larger than the sum of its proper divisors (1806299).

13431781 is a wasteful number, since it uses less digits than its factorization.

13431781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 516.

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

The square root of 13431781 is about 3664.9394265117. The cubic root of 13431781 is about 237.7084028562.

The spelling of 13431781 in words is "thirteen million, four hundred thirty-one thousand, seven hundred eighty-one".