21131602 has 8 divisors (see below), whose sum is σ = 32131836. Its totient is φ = 10420992.

The previous prime is 21131597. The next prime is 21131651. The reversal of 21131602 is 20613112.

It can be written as a sum of positive squares in 2 ways, for example, as 19811401 + 1320201 = 4451^2 + 1149^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72223 + ... + 72514.

Almost surely, 2^21131602 is an apocalyptic number.

21131602 is a deficient number, since it is larger than the sum of its proper divisors (11000234).

21131602 is a wasteful number, since it uses less digits than its factorization.

21131602 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 144812.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 21131602 is about 4596.9122245264. The cubic root of 21131602 is about 276.4675352950.

Adding to 21131602 its reverse (20613112), we get a palindrome (41744714).

It can be divided in two parts, 211 and 31602, that added together give a palindrome (31813).

The spelling of 21131602 in words is "twenty-one million, one hundred thirty-one thousand, six hundred two".