21988027 has 4 divisors (see below), whose sum is σ = 22582336. Its totient is φ = 21393720.

The previous prime is 21988019. The next prime is 21988037. The reversal of 21988027 is 72088912.

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

It is a cyclic number.

It is not a de Polignac number, because 21988027 - 2³ = 21988019 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37), and also a Moran number because the ratio is a prime number: 594271 = 21988027 / (2 + 1 + 9 + 8 + 8 + 0 + 2 + 7).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21988037) 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, 297099 + ... + 297172.

It is an arithmetic number, because the mean of its divisors is an integer number (5645584).

Almost surely, 2^21988027 is an apocalyptic number.

21988027 is a deficient number, since it is larger than the sum of its proper divisors (594309).

21988027 is an equidigital number, since it uses as much as digits as its factorization.

21988027 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 594308.

The product of its (nonzero) digits is 16128, while the sum is 37.

The square root of 21988027 is about 4689.1392600348. The cubic root of 21988027 is about 280.1530923007.

The spelling of 21988027 in words is "twenty-one million, nine hundred eighty-eight thousand, twenty-seven".