20227981 has 4 divisors (see below), whose sum is σ = 20259612. Its totient is φ = 20196352.

The previous prime is 20227969. The next prime is 20227997. The reversal of 20227981 is 18972202.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14891881 + 5336100 = 3859^2 + 2310^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20227981 is a prime.

It is a super-2 number, since 2×20227981² = 818342430672722, which contains 22 as substring.

It is a pancake number, because a pancake can be divided into 20227981 parts by 6360 straight cuts.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20227901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14836 + ... + 16141.

It is an arithmetic number, because the mean of its divisors is an integer number (5064903).

Almost surely, 2^20227981 is an apocalyptic number.

It is an amenable number.

20227981 is a deficient number, since it is larger than the sum of its proper divisors (31631).

20227981 is an equidigital number, since it uses as much as digits as its factorization.

20227981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31630.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 20227981 is about 4497.5527790122. The cubic root of 20227981 is about 272.4692600625.

The spelling of 20227981 in words is "twenty million, two hundred twenty-seven thousand, nine hundred eighty-one".