21956479 has 2 divisors, whose sum is σ = 21956480. Its totient is φ = 21956478.

The previous prime is 21956471. The next prime is 21956527. The reversal of 21956479 is 97465912.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21956479 - 2³ = 21956471 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21956471) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10978239 + 10978240.

It is an arithmetic number, because the mean of its divisors is an integer number (10978240).

Almost surely, 2^21956479 is an apocalyptic number.

21956479 is a deficient number, since it is larger than the sum of its proper divisors (1).

21956479 is an equidigital number, since it uses as much as digits as its factorization.

21956479 is an evil number, because the sum of its binary digits is even.

The product of its digits is 136080, while the sum is 43.

The square root of 21956479 is about 4685.7741089387. The cubic root of 21956479 is about 280.0190420723.

The spelling of 21956479 in words is "twenty-one million, nine hundred fifty-six thousand, four hundred seventy-nine".