21925871 has 4 divisors (see below), whose sum is σ = 23919144. Its totient is φ = 19932600.

The previous prime is 21925853. The next prime is 21925879. The reversal of 21925871 is 17852912.

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 21925871 - 2⁶ = 21925807 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21925879) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 996620 + ... + 996641.

It is an arithmetic number, because the mean of its divisors is an integer number (5979786).

Almost surely, 2^21925871 is an apocalyptic number.

21925871 is a deficient number, since it is larger than the sum of its proper divisors (1993273).

21925871 is a wasteful number, since it uses less digits than its factorization.

21925871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1993272.

The product of its digits is 10080, while the sum is 35.

The square root of 21925871 is about 4682.5069140365. The cubic root of 21925871 is about 279.8888632067. Note that the first 4 decimals are identical.

The spelling of 21925871 in words is "twenty-one million, nine hundred twenty-five thousand, eight hundred seventy-one".