21225559 has 2 divisors, whose sum is σ = 21225560. Its totient is φ = 21225558.

The previous prime is 21225551. The next prime is 21225563. The reversal of 21225559 is 95552212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21225559 - 2³ = 21225551 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21225559.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21225551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10612779 + 10612780.

It is an arithmetic number, because the mean of its divisors is an integer number (10612780).

Almost surely, 2^21225559 is an apocalyptic number.

21225559 is a deficient number, since it is larger than the sum of its proper divisors (1).

21225559 is an equidigital number, since it uses as much as digits as its factorization.

21225559 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9000, while the sum is 31.

The square root of 21225559 is about 4607.1204672767. The cubic root of 21225559 is about 276.8766801088.

The spelling of 21225559 in words is "twenty-one million, two hundred twenty-five thousand, five hundred fifty-nine".