21124907 has 4 divisors (see below), whose sum is σ = 21141120. Its totient is φ = 21108696.

The previous prime is 21124877. The next prime is 21124927. The reversal of 21124907 is 70942112.

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 21124907 - 2¹² = 21120811 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21124927) 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, 5963 + ... + 8820.

It is an arithmetic number, because the mean of its divisors is an integer number (5285280).

Almost surely, 2^21124907 is an apocalyptic number.

21124907 is a deficient number, since it is larger than the sum of its proper divisors (16213).

21124907 is a wasteful number, since it uses less digits than its factorization.

21124907 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16212.

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

The square root of 21124907 is about 4596.1839606352. The cubic root of 21124907 is about 276.4383350218.

The spelling of 21124907 in words is "twenty-one million, one hundred twenty-four thousand, nine hundred seven".