12001781 has 4 divisors (see below), whose sum is σ = 13092864. Its totient is φ = 10910700.

The previous prime is 12001763. The next prime is 12001799. The reversal of 12001781 is 18710021.

12001781 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (12001763) and next prime (12001799).

It is a cyclic number.

It is not a de Polignac number, because 12001781 - 2¹⁰ = 12000757 is a prime.

It is a super-2 number, since 2×12001781² = 288085494343922, 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 (12001081) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 545525 + ... + 545546.

It is an arithmetic number, because the mean of its divisors is an integer number (3273216).

Almost surely, 2^12001781 is an apocalyptic number.

12001781 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12001781 is a deficient number, since it is larger than the sum of its proper divisors (1091083).

12001781 is a wasteful number, since it uses less digits than its factorization.

12001781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1091082.

The product of its (nonzero) digits is 112, while the sum is 20.

The square root of 12001781 is about 3464.3586708076. The cubic root of 12001781 is about 228.9541742619.

The spelling of 12001781 in words is "twelve million, one thousand, seven hundred eighty-one".