27399981 has 16 divisors (see below), whose sum is σ = 41827968. Its totient is φ = 15628800.

The previous prime is 27399959. The next prime is 27399989. The reversal of 27399981 is 18999372.

It is not a de Polignac number, because 27399981 - 2⁵ = 27399949 is a prime.

It is a super-2 number, since 2×27399981² = 1501517917600722, which contains 22 as substring.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 27399981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27399989) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17761 + ... + 19241.

It is an arithmetic number, because the mean of its divisors is an integer number (2614248).

Almost surely, 2^27399981 is an apocalyptic number.

27399981 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

27399981 is a deficient number, since it is larger than the sum of its proper divisors (14427987).

27399981 is a wasteful number, since it uses less digits than its factorization.

27399981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2372.

The product of its digits is 244944, while the sum is 48.

The square root of 27399981 is about 5234.4991164389. The cubic root of 27399981 is about 301.4741554650.

It can be divided in two parts, 2739 and 9981, that added together give a triangular number (12720 = T₁₅₉).

The spelling of 27399981 in words is "twenty-seven million, three hundred ninety-nine thousand, nine hundred eighty-one".