21970427 has 2 divisors, whose sum is σ = 21970428. Its totient is φ = 21970426.

The previous prime is 21970397. The next prime is 21970433. The reversal of 21970427 is 72407912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21970427 - 2⁶ = 21970363 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21970393 and 21970402.

It is not a weakly prime, because it can be changed into another prime (21970447) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10985213 + 10985214.

It is an arithmetic number, because the mean of its divisors is an integer number (10985214).

Almost surely, 2^21970427 is an apocalyptic number.

21970427 is a deficient number, since it is larger than the sum of its proper divisors (1).

21970427 is an equidigital number, since it uses as much as digits as its factorization.

21970427 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7056, while the sum is 32.

The square root of 21970427 is about 4687.2622073018. The cubic root of 21970427 is about 280.0783241768.

The spelling of 21970427 in words is "twenty-one million, nine hundred seventy thousand, four hundred twenty-seven".