21222501 has 4 divisors (see below), whose sum is σ = 28296672. Its totient is φ = 14148332.

The previous prime is 21222499. The next prime is 21222503. The reversal of 21222501 is 10522212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (21222499) and next prime (21222503).

It is a cyclic number.

It is not a de Polignac number, because 21222501 - 2¹ = 21222499 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21222503) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3537081 + ... + 3537086.

It is an arithmetic number, because the mean of its divisors is an integer number (7074168).

Almost surely, 2^21222501 is an apocalyptic number.

It is an amenable number.

21222501 is a deficient number, since it is larger than the sum of its proper divisors (7074171).

21222501 is an equidigital number, since it uses as much as digits as its factorization.

21222501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7074170.

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 21222501 is about 4606.7885777405. The cubic root of 21222501 is about 276.8633827825.

Adding to 21222501 its reverse (10522212), we get a palindrome (31744713).

The spelling of 21222501 in words is "twenty-one million, two hundred twenty-two thousand, five hundred one".