21512002 has 4 divisors (see below), whose sum is σ = 32268006. Its totient is φ = 10756000.

The previous prime is 21511999. The next prime is 21512017. The reversal of 21512002 is 20021512.

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., 21150801 + 361201 = 4599^2 + 601^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5377999 + ... + 5378002.

Almost surely, 2^21512002 is an apocalyptic number.

21512002 is a deficient number, since it is larger than the sum of its proper divisors (10756004).

21512002 is a wasteful number, since it uses less digits than its factorization.

21512002 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10756003.

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 21512002 is about 4638.1032761248. The cubic root of 21512002 is about 278.1166203257.

Adding to 21512002 its reverse (20021512), we get a palindrome (41533514).

The spelling of 21512002 in words is "twenty-one million, five hundred twelve thousand, two".