21251002106 has 8 divisors (see below), whose sum is σ = 31918614420. Its totient is φ = 10611463968.

The previous prime is 21251002103. The next prime is 21251002109. The reversal of 21251002106 is 60120015212.

It is an interprime number because it is at equal distance from previous prime (21251002103) and next prime (21251002109).

It can be written as a sum of positive squares in 2 ways, for example, as 20839520881 + 411481225 = 144359^2 + 20285^2 .

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

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21251002103) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7016651 + ... + 7019678.

Almost surely, 2^21251002106 is an apocalyptic number.

21251002106 is a deficient number, since it is larger than the sum of its proper divisors (10667612314).

21251002106 is a wasteful number, since it uses less digits than its factorization.

21251002106 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14037088.

The product of its (nonzero) digits is 240, while the sum is 20.

Adding to 21251002106 its reverse (60120015212), we get a palindrome (81371017318).

The spelling of 21251002106 in words is "twenty-one billion, two hundred fifty-one million, two thousand, one hundred six".