10999981 has 4 divisors (see below), whose sum is σ = 11016000. Its totient is φ = 10983964.

The previous prime is 10999979. The next prime is 10999987. The reversal of 10999981 is 18999901.

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 a cyclic number.

It is not a de Polignac number, because 10999981 - 2¹ = 10999979 is a prime.

It is a super-2 number, since 2×10999981² = 241999164000722, 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 (10999987) 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, 6931 + ... + 8368.

It is an arithmetic number, because the mean of its divisors is an integer number (2754000).

Almost surely, 2^10999981 is an apocalyptic number.

It is an amenable number.

10999981 is a deficient number, since it is larger than the sum of its proper divisors (16019).

10999981 is an equidigital number, since it uses as much as digits as its factorization.

10999981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16018.

The product of its (nonzero) digits is 52488, while the sum is 46.

The square root of 10999981 is about 3316.6219259964. The cubic root of 10999981 is about 222.3978810095.

The spelling of 10999981 in words is "ten million, nine hundred ninety-nine thousand, nine hundred eighty-one".