21435657 has 8 divisors (see below), whose sum is σ = 30262176. Its totient is φ = 13449792.

The previous prime is 21435643. The next prime is 21435677. The reversal of 21435657 is 75653412.

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

It is not a de Polignac number, because 21435657 - 2⁶ = 21435593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21435677) 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, 210103 + ... + 210204.

It is an arithmetic number, because the mean of its divisors is an integer number (3782772).

Almost surely, 2^21435657 is an apocalyptic number.

It is an amenable number.

21435657 is a deficient number, since it is larger than the sum of its proper divisors (8826519).

21435657 is a wasteful number, since it uses less digits than its factorization.

21435657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 420327.

The product of its digits is 25200, while the sum is 33.

The square root of 21435657 is about 4629.8657647928. The cubic root of 21435657 is about 277.7872231040.

The spelling of 21435657 in words is "twenty-one million, four hundred thirty-five thousand, six hundred fifty-seven".