27972121 has 4 divisors (see below), whose sum is σ = 28094500. Its totient is φ = 27849744.

The previous prime is 27972107. The next prime is 27972169. The reversal of 27972121 is 12127972.

It is a happy number.

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 20070400 + 7901721 = 4480^2 + 2811^2 .

It is a cyclic number.

It is not a de Polignac number, because 27972121 - 2²³ = 19583513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (27972421) 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, 60846 + ... + 61303.

It is an arithmetic number, because the mean of its divisors is an integer number (7023625).

Almost surely, 2^27972121 is an apocalyptic number.

It is an amenable number.

27972121 is a deficient number, since it is larger than the sum of its proper divisors (122379).

27972121 is a wasteful number, since it uses less digits than its factorization.

27972121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122378.

The product of its digits is 3528, while the sum is 31.

The square root of 27972121 is about 5288.8676481833. The cubic root of 27972121 is about 303.5580815012.

The spelling of 27972121 in words is "twenty-seven million, nine hundred seventy-two thousand, one hundred twenty-one".