21500002 has 8 divisors (see below), whose sum is σ = 34147116. Its totient is φ = 10117632.

The previous prime is 21499981. The next prime is 21500021. The reversal of 21500002 is 20000512.

It can be written as a sum of positive squares in 2 ways, for example, as 21427641 + 72361 = 4629^2 + 269^2 .

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

It is a super-3 number, since 3×21500002³ (a number of 23 digits) contains 333 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 316143 + ... + 316210.

Almost surely, 2^21500002 is an apocalyptic number.

21500002 is a deficient number, since it is larger than the sum of its proper divisors (12647114).

21500002 is a wasteful number, since it uses less digits than its factorization.

21500002 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 632372.

The product of its (nonzero) digits is 20, while the sum is 10.

The square root of 21500002 is about 4636.8094634134. The cubic root of 21500002 is about 278.0648969482.

Adding to 21500002 its reverse (20000512), we get a palindrome (41500514).

The spelling of 21500002 in words is "twenty-one million, five hundred thousand, two".