21952247 has 4 divisors (see below), whose sum is σ = 22660416. Its totient is φ = 21244080.

The previous prime is 21952207. The next prime is 21952291. The reversal of 21952247 is 74225912.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21952247 - 2⁸ = 21951991 is a prime.

It is a super-2 number, since 2×21952247² = 963802296698018, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21952207) 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, 354038 + ... + 354099.

It is an arithmetic number, because the mean of its divisors is an integer number (5665104).

Almost surely, 2^21952247 is an apocalyptic number.

21952247 is a deficient number, since it is larger than the sum of its proper divisors (708169).

21952247 is an equidigital number, since it uses as much as digits as its factorization.

21952247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 708168.

The product of its digits is 10080, while the sum is 32.

The square root of 21952247 is about 4685.3225075762. The cubic root of 21952247 is about 280.0010501661.

The spelling of 21952247 in words is "twenty-one million, nine hundred fifty-two thousand, two hundred forty-seven".