21907241 has 4 divisors (see below), whose sum is σ = 21921492. Its totient is φ = 21892992.

The previous prime is 21907229. The next prime is 21907279. The reversal of 21907241 is 14270912.

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

It can be written as a sum of positive squares in 2 ways, for example, as 4932841 + 16974400 = 2221^2 + 4120^2 .

It is a cyclic number.

It is not a de Polignac number, because 21907241 - 2⁶ = 21907177 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21907241.

It is not an unprimeable number, because it can be changed into a prime (21907541) 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, 4496 + ... + 8001.

It is an arithmetic number, because the mean of its divisors is an integer number (5480373).

Almost surely, 2^21907241 is an apocalyptic number.

It is an amenable number.

21907241 is a deficient number, since it is larger than the sum of its proper divisors (14251).

21907241 is a wasteful number, since it uses less digits than its factorization.

21907241 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14250.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 21907241 is about 4680.5171722791. The cubic root of 21907241 is about 279.8095686440.

The spelling of 21907241 in words is "twenty-one million, nine hundred seven thousand, two hundred forty-one".