21435857 has 8 divisors (see below), whose sum is σ = 22641600. Its totient is φ = 20237904.

The previous prime is 21435853. The next prime is 21435859. The reversal of 21435857 is 75853412.

It is a happy number.

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 21435857 - 2² = 21435853 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21435853) 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, 4244 + ... + 7802.

It is an arithmetic number, because the mean of its divisors is an integer number (2830200).

Almost surely, 2^21435857 is an apocalyptic number.

It is an amenable number.

21435857 is a deficient number, since it is larger than the sum of its proper divisors (1205743).

21435857 is a wasteful number, since it uses less digits than its factorization.

21435857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3895.

The product of its digits is 33600, while the sum is 35.

The square root of 21435857 is about 4629.8873636407. The cubic root of 21435857 is about 277.7880870426.

It can be divided in two parts, 2143 and 5857, that added together give a cube (8000 = 20³).

The spelling of 21435857 in words is "twenty-one million, four hundred thirty-five thousand, eight hundred fifty-seven".