27978208207 has 4 divisors (see below), whose sum is σ = 27978549640. Its totient is φ = 27977866776.

The previous prime is 27978208183. The next prime is 27978208249. The reversal of 27978208207 is 70280287972.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a 3-Lehmer number, since φ(27978208207) divides (27978208207-1)³.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-27978208207 is a prime.

It is a deceptive number, since it divides R_27978208206.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27978208607) 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, 34144 + ... + 239002.

It is an arithmetic number, because the mean of its divisors is an integer number (6994637410).

Almost surely, 2^27978208207 is an apocalyptic number.

27978208207 is the 136573-rd pentagonal number.

27978208207 is a deficient number, since it is larger than the sum of its proper divisors (341433).

27978208207 is a wasteful number, since it uses less digits than its factorization.

27978208207 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 341432.

The product of its (nonzero) digits is 1580544, while the sum is 52.

The spelling of 27978208207 in words is "twenty-seven billion, nine hundred seventy-eight million, two hundred eight thousand, two hundred seven".