21235402 has 4 divisors (see below), whose sum is σ = 31853106. Its totient is φ = 10617700.

The previous prime is 21235367. The next prime is 21235427. The reversal of 21235402 is 20453212.

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

It can be written as a sum of positive squares in only one way, i.e., 15848361 + 5387041 = 3981^2 + 2321^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21235402.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5308849 + ... + 5308852.

Almost surely, 2^21235402 is an apocalyptic number.

21235402 is a deficient number, since it is larger than the sum of its proper divisors (10617704).

21235402 is a wasteful number, since it uses less digits than its factorization.

21235402 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10617703.

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 21235402 is about 4608.1885812106. The cubic root of 21235402 is about 276.9194724800.

Adding to 21235402 its reverse (20453212), we get a palindrome (41688614).

The spelling of 21235402 in words is "twenty-one million, two hundred thirty-five thousand, four hundred two".