21827972 has 6 divisors (see below), whose sum is σ = 38198958. Its totient is φ = 10913984.

The previous prime is 21827951. The next prime is 21827977. The reversal of 21827972 is 27972812.

It can be written as a sum of positive squares in only one way, i.e., 21752896 + 75076 = 4664^2 + 274^2 .

It is not an unprimeable number, because it can be changed into a prime (21827977) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2728493 + ... + 2728500.

It is an arithmetic number, because the mean of its divisors is an integer number (6366493).

Almost surely, 2^21827972 is an apocalyptic number.

It is an amenable number.

21827972 is a deficient number, since it is larger than the sum of its proper divisors (16370986).

21827972 is a wasteful number, since it uses less digits than its factorization.

21827972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5456997 (or 5456995 counting only the distinct ones).

The product of its digits is 28224, while the sum is 38.

The square root of 21827972 is about 4672.0415237881. The cubic root of 21827972 is about 279.4716738073.

The spelling of 21827972 in words is "twenty-one million, eight hundred twenty-seven thousand, nine hundred seventy-two".