27721397 has 4 divisors (see below), whose sum is σ = 30241536. Its totient is φ = 25201260.

The previous prime is 27721387. The next prime is 27721427. The reversal of 27721397 is 79312772.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 27721397 - 2¹⁸ = 27459253 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 27721397.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27721357) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1260053 + ... + 1260074.

It is an arithmetic number, because the mean of its divisors is an integer number (7560384).

Almost surely, 2^27721397 is an apocalyptic number.

It is an amenable number.

27721397 is a deficient number, since it is larger than the sum of its proper divisors (2520139).

27721397 is a wasteful number, since it uses less digits than its factorization.

27721397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2520138.

The product of its digits is 37044, while the sum is 38.

The square root of 27721397 is about 5265.1112998682. Note that the first 3 decimals coincide. The cubic root of 27721397 is about 302.6483920075.

The spelling of 27721397 in words is "twenty-seven million, seven hundred twenty-one thousand, three hundred ninety-seven".