21522370 has 16 divisors (see below), whose sum is σ = 39990528. Its totient is φ = 8331120.

The previous prime is 21522367. The next prime is 21522373. The reversal of 21522370 is 7322512.

It is an interprime number because it is at equal distance from previous prime (21522367) and next prime (21522373).

It is not an unprimeable number, because it can be changed into a prime (21522373) 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, 34404 + ... + 35023.

It is an arithmetic number, because the mean of its divisors is an integer number (2499408).

Almost surely, 2^21522370 is an apocalyptic number.

21522370 is a deficient number, since it is larger than the sum of its proper divisors (18468158).

21522370 is a wasteful number, since it uses less digits than its factorization.

21522370 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69465.

The product of its (nonzero) digits is 840, while the sum is 22.

The square root of 21522370 is about 4639.2208397532. The cubic root of 21522370 is about 278.1612938371.

Adding to 21522370 its reverse (7322512), we get a palindrome (28844882).

The spelling of 21522370 in words is "twenty-one million, five hundred twenty-two thousand, three hundred seventy".