21251052071 has 8 divisors (see below), whose sum is σ = 21987097920. Its totient is φ = 20515223008.

The previous prime is 21251052049. The next prime is 21251052073. The reversal of 21251052071 is 17025015212.

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

It is a cyclic number.

It is not a de Polignac number, because 21251052071 - 2⁶ = 21251052007 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21251052071.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21251052073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 159605 + ... + 260721.

It is an arithmetic number, because the mean of its divisors is an integer number (2748387240).

Almost surely, 2^21251052071 is an apocalyptic number.

21251052071 is a deficient number, since it is larger than the sum of its proper divisors (736045849).

21251052071 is a wasteful number, since it uses less digits than its factorization.

21251052071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108393.

The product of its (nonzero) digits is 1400, while the sum is 26.

Adding to 21251052071 its reverse (17025015212), we get a palindrome (38276067283).

The spelling of 21251052071 in words is "twenty-one billion, two hundred fifty-one million, fifty-two thousand, seventy-one".