21385235 has 32 divisors (see below), whose sum is σ = 28553472. Its totient is φ = 15308800.

The previous prime is 21385211. The next prime is 21385237. The reversal of 21385235 is 53258312.

It is not a de Polignac number, because 21385235 - 2¹⁶ = 21319699 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21385198 and 21385207.

It is not an unprimeable number, because it can be changed into a prime (21385237) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 211685 + ... + 211785.

It is an arithmetic number, because the mean of its divisors is an integer number (892296).

Almost surely, 2^21385235 is an apocalyptic number.

21385235 is a deficient number, since it is larger than the sum of its proper divisors (7168237).

21385235 is a wasteful number, since it uses less digits than its factorization.

21385235 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223.

The product of its digits is 7200, while the sum is 29.

The square root of 21385235 is about 4624.4172605854. The cubic root of 21385235 is about 277.5692438734.

The spelling of 21385235 in words is "twenty-one million, three hundred eighty-five thousand, two hundred thirty-five".