11990781 has 32 divisors (see below), whose sum is σ = 19814400. Its totient is φ = 7104240.

The previous prime is 11990779. The next prime is 11990791. The reversal of 11990781 is 18709911.

It is not a de Polignac number, because 11990781 - 2¹ = 11990779 is a prime.

It is a super-2 number, since 2×11990781² = 287557657979922, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11990791) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 13530 + ... + 14388.

It is an arithmetic number, because the mean of its divisors is an integer number (619200).

Almost surely, 2^11990781 is an apocalyptic number.

11990781 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

11990781 is a deficient number, since it is larger than the sum of its proper divisors (7823619).

11990781 is a wasteful number, since it uses less digits than its factorization.

11990781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 926 (or 920 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 36.

The square root of 11990781 is about 3462.7707114390. The cubic root of 11990781 is about 228.8842050427.

The spelling of 11990781 in words is "eleven million, nine hundred ninety thousand, seven hundred eighty-one".