27821987 has 2 divisors, whose sum is σ = 27821988. Its totient is φ = 27821986.

The previous prime is 27821977. The next prime is 27821993. The reversal of 27821987 is 78912872.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 27821987 - 2⁴ = 27821971 is a prime.

It is a super-3 number, since 3×27821987³ (a number of 23 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (27821977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13910993 + 13910994.

It is an arithmetic number, because the mean of its divisors is an integer number (13910994).

Almost surely, 2^27821987 is an apocalyptic number.

27821987 is a deficient number, since it is larger than the sum of its proper divisors (1).

27821987 is an equidigital number, since it uses as much as digits as its factorization.

27821987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 112896, while the sum is 44.

The square root of 27821987 is about 5274.6551546049. The cubic root of 27821987 is about 303.0140139546.

The spelling of 27821987 in words is "twenty-seven million, eight hundred twenty-one thousand, nine hundred eighty-seven".