27742451021 has 4 divisors (see below), whose sum is σ = 27746849052. Its totient is φ = 27738052992.

The previous prime is 27742451017. The next prime is 27742451041. The reversal of 27742451021 is 12015424772.

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 16354573225 + 11387877796 = 127885^2 + 106714^2 .

It is a cyclic number.

It is not a de Polignac number, because 27742451021 - 2² = 27742451017 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27742451041) 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, 2189540 + ... + 2202173.

It is an arithmetic number, because the mean of its divisors is an integer number (6936712263).

Almost surely, 2^27742451021 is an apocalyptic number.

It is an amenable number.

27742451021 is a deficient number, since it is larger than the sum of its proper divisors (4398031).

27742451021 is an equidigital number, since it uses as much as digits as its factorization.

27742451021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4398030.

The product of its (nonzero) digits is 31360, while the sum is 35.

Adding to 27742451021 its reverse (12015424772), we get a palindrome (39757875793).

The spelling of 27742451021 in words is "twenty-seven billion, seven hundred forty-two million, four hundred fifty-one thousand, twenty-one".