21956427 has 10 divisors (see below), whose sum is σ = 32799228. Its totient is φ = 14637564.

The previous prime is 21956423. The next prime is 21956461. The reversal of 21956427 is 72465912.

21956427 is a `hidden beast` number, since 2 + 1 + 9 + 5 + 642 + 7 = 666.

It is not a de Polignac number, because 21956427 - 2² = 21956423 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21956391 and 21956400.

It is not an unprimeable number, because it can be changed into a prime (21956423) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 135453 + ... + 135614.

Almost surely, 2^21956427 is an apocalyptic number.

21956427 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21956427 is a deficient number, since it is larger than the sum of its proper divisors (10842801).

21956427 is an equidigital number, since it uses as much as digits as its factorization.

21956427 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 271079 (or 271070 counting only the distinct ones).

The product of its digits is 30240, while the sum is 36.

The square root of 21956427 is about 4685.7685602257. The cubic root of 21956427 is about 280.0188210138.

The spelling of 21956427 in words is "twenty-one million, nine hundred fifty-six thousand, four hundred twenty-seven".