21388435 has 8 divisors (see below), whose sum is σ = 25716816. Its totient is φ = 17076960.

The previous prime is 21388421. The next prime is 21388439. The reversal of 21388435 is 53488312.

It is a happy number.

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

It is not a de Polignac number, because 21388435 - 2¹⁵ = 21355667 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21388435.

It is not an unprimeable number, because it can be changed into a prime (21388439) 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, 1249 + ... + 6658.

It is an arithmetic number, because the mean of its divisors is an integer number (3214602).

Almost surely, 2^21388435 is an apocalyptic number.

21388435 is a deficient number, since it is larger than the sum of its proper divisors (4328381).

21388435 is an equidigital number, since it uses as much as digits as its factorization.

21388435 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8453.

The product of its digits is 23040, while the sum is 34.

The square root of 21388435 is about 4624.7632371831. The cubic root of 21388435 is about 277.5830879622.

The spelling of 21388435 in words is "twenty-one million, three hundred eighty-eight thousand, four hundred thirty-five".