21522270 has 120 divisors (see below), whose sum is σ = 66094920. Its totient is φ = 4472160.

The previous prime is 21522257. The next prime is 21522283. The reversal of 21522270 is 7222512.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21522257) and next prime (21522283).

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 1956565 + ... + 1956575.

It is an arithmetic number, because the mean of its divisors is an integer number (550791).

Almost surely, 2^21522270 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21522270, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33047460).

21522270 is an abundant number, since it is smaller than the sum of its proper divisors (44572650).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21522270 is an equidigital number, since it uses as much as digits as its factorization.

21522270 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68 (or 28 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 21.

The square root of 21522270 is about 4639.2100620688. The cubic root of 21522270 is about 278.1608630268.

Adding to 21522270 its reverse (7222512), we get a palindrome (28744782).

The spelling of 21522270 in words is "twenty-one million, five hundred twenty-two thousand, two hundred seventy".