21435139 has 4 divisors (see below), whose sum is σ = 23383800. Its totient is φ = 19486480.

The previous prime is 21435133. The next prime is 21435143. The reversal of 21435139 is 93153412.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21435139 - 2⁵ = 21435107 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21435133) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 974314 + ... + 974335.

It is an arithmetic number, because the mean of its divisors is an integer number (5845950).

Almost surely, 2^21435139 is an apocalyptic number.

21435139 is a deficient number, since it is larger than the sum of its proper divisors (1948661).

21435139 is a wasteful number, since it uses less digits than its factorization.

21435139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1948660.

The product of its digits is 3240, while the sum is 28.

The square root of 21435139 is about 4629.8098233081. The cubic root of 21435139 is about 277.7849854782.

It can be divided in two parts, 214 and 35139, that added together give a palindrome (35353).

The spelling of 21435139 in words is "twenty-one million, four hundred thirty-five thousand, one hundred thirty-nine".