21217047540826 has 16 divisors (see below), whose sum is σ = 34354439798400. Its totient is φ = 9797377274608.

The previous prime is 21217047540823. The next prime is 21217047540883. The reversal of 21217047540826 is 62804574071212.

It is a super-2 number, since 2×21217047540826² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21217047540826.

It is not an unprimeable number, because it can be changed into a prime (21217047540823) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7952415286 + ... + 7952417953.

It is an arithmetic number, because the mean of its divisors is an integer number (2147152487400).

Almost surely, 2^{21217047540826} is an apocalyptic number.

21217047540826 is a deficient number, since it is larger than the sum of its proper divisors (13137392257574).

21217047540826 is a wasteful number, since it uses less digits than its factorization.

21217047540826 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15904833293.

The product of its (nonzero) digits is 1505280, while the sum is 49.

The spelling of 21217047540826 in words is "twenty-one trillion, two hundred seventeen billion, forty-seven million, five hundred forty thousand, eight hundred twenty-six".