21125251006717 has 32 divisors (see below), whose sum is σ = 26181879534720. Its totient is φ = 16757707576320.

The previous prime is 21125251006709. The next prime is 21125251006729. The reversal of 21125251006717 is 71760015252112.

It is not a de Polignac number, because 21125251006717 - 2³ = 21125251006709 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21125251006717.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21125251006817) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7265128 + ... + 9748465.

It is an arithmetic number, because the mean of its divisors is an integer number (818183735460).

Almost surely, 2^{21125251006717} is an apocalyptic number.

It is an amenable number.

21125251006717 is a deficient number, since it is larger than the sum of its proper divisors (5056628528003).

21125251006717 is a wasteful number, since it uses less digits than its factorization.

21125251006717 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17014093.

The product of its (nonzero) digits is 58800, while the sum is 40.

Adding to 21125251006717 its reverse (71760015252112), we get a palindrome (92885266258829).

The spelling of 21125251006717 in words is "twenty-one trillion, one hundred twenty-five billion, two hundred fifty-one million, six thousand, seven hundred seventeen".