11251981 has 4 divisors (see below), whose sum is σ = 12117532. Its totient is φ = 10386432.

The previous prime is 11251979. The next prime is 11252023. The reversal of 11251981 is 18915211.

11251981 is digitally balanced in base 2, 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 an emirpimes, since its reverse is a distinct semiprime: 18915211 = 7 ⋅2702173.

It can be written as a sum of positive squares in 2 ways, for example, as 585225 + 10666756 = 765^2 + 3266^2 .

It is a cyclic number.

It is not a de Polignac number, because 11251981 - 2¹ = 11251979 is a prime.

It is a super-2 number, since 2×11251981² = 253214152848722, 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 (11251901) 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, 432756 + ... + 432781.

It is an arithmetic number, because the mean of its divisors is an integer number (3029383).

Almost surely, 2^11251981 is an apocalyptic number.

It is an amenable number.

11251981 is a deficient number, since it is larger than the sum of its proper divisors (865551).

11251981 is an equidigital number, since it uses as much as digits as its factorization.

11251981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 865550.

The product of its digits is 720, while the sum is 28.

The square root of 11251981 is about 3354.3972632949. The cubic root of 11251981 is about 224.0833886490.

The spelling of 11251981 in words is "eleven million, two hundred fifty-one thousand, nine hundred eighty-one".