21305707 has 8 divisors (see below), whose sum is σ = 22735760. Its totient is φ = 19906560.

The previous prime is 21305699. The next prime is 21305719. The reversal of 21305707 is 70750312.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21305707 - 2³ = 21305699 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21305737) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6294 + ... + 9067.

It is an arithmetic number, because the mean of its divisors is an integer number (2841970).

Almost surely, 2^21305707 is an apocalyptic number.

21305707 is a deficient number, since it is larger than the sum of its proper divisors (1430053).

21305707 is a wasteful number, since it uses less digits than its factorization.

21305707 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15453.

The product of its (nonzero) digits is 1470, while the sum is 25.

The square root of 21305707 is about 4615.8105463721. The cubic root of 21305707 is about 277.2247390895.

The spelling of 21305707 in words is "twenty-one million, three hundred five thousand, seven hundred seven".