13001781 has 16 divisors (see below), whose sum is σ = 19105856. Its totient is φ = 7814016.

The previous prime is 13001761. The next prime is 13001789. The reversal of 13001781 is 18710031.

It is not a de Polignac number, because 13001781 - 2⁵ = 13001749 is a prime.

It is a super-2 number, since 2×13001781² = 338092618343922, 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 (13001789) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 2200 + ... + 5553.

It is an arithmetic number, because the mean of its divisors is an integer number (1194116).

Almost surely, 2^13001781 is an apocalyptic number.

It is an amenable number.

13001781 is a deficient number, since it is larger than the sum of its proper divisors (6104075).

13001781 is a wasteful number, since it uses less digits than its factorization.

13001781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7812.

The product of its (nonzero) digits is 168, while the sum is 21.

The square root of 13001781 is about 3605.7982472679. The cubic root of 13001781 is about 235.1442060435.

It can be divided in two parts, 1300 and 1781, that added together give a triangular number (3081 = T₇₈).

The spelling of 13001781 in words is "thirteen million, one thousand, seven hundred eighty-one".