21225577 has 8 divisors (see below), whose sum is σ = 21810600. Its totient is φ = 20643840.

The previous prime is 21225563. The next prime is 21225583. The reversal of 21225577 is 77552212.

It can be written as a sum of positive squares in 4 ways, for example, as 2119936 + 19105641 = 1456^2 + 4371^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21225577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21225077) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17833 + ... + 18985.

It is an arithmetic number, because the mean of its divisors is an integer number (2726325).

Almost surely, 2^21225577 is an apocalyptic number.

It is an amenable number.

21225577 is a deficient number, since it is larger than the sum of its proper divisors (585023).

21225577 is a wasteful number, since it uses less digits than its factorization.

21225577 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1643.

The product of its digits is 9800, while the sum is 31.

The square root of 21225577 is about 4607.1224207742. The cubic root of 21225577 is about 276.8767583757.

Adding to 21225577 its reverse (77552212), we get a palindrome (98777789).

The spelling of 21225577 in words is "twenty-one million, two hundred twenty-five thousand, five hundred seventy-seven".