21305877 has 8 divisors (see below), whose sum is σ = 28444416. Its totient is φ = 14185632.

The previous prime is 21305857. The next prime is 21305891. The reversal of 21305877 is 77850312.

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

It is not a de Polignac number, because 21305877 - 2¹⁴ = 21289493 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21305857) 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, 1573 + ... + 6714.

It is an arithmetic number, because the mean of its divisors is an integer number (3555552).

Almost surely, 2^21305877 is an apocalyptic number.

It is an amenable number.

21305877 is a deficient number, since it is larger than the sum of its proper divisors (7138539).

21305877 is an equidigital number, since it uses as much as digits as its factorization.

21305877 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9147.

The product of its (nonzero) digits is 11760, while the sum is 33.

The square root of 21305877 is about 4615.8289613026. The cubic root of 21305877 is about 277.2254764205.

The spelling of 21305877 in words is "twenty-one million, three hundred five thousand, eight hundred seventy-seven".