21357172226655 has 16 divisors (see below), whose sum is σ = 37968306180960. Its totient is φ = 11390491854144.

The previous prime is 21357172226651. The next prime is 21357172226669. The reversal of 21357172226655 is 55662227175312.

21357172226655 is a `hidden beast` number, since 2 + 1 + 3 + 571 + 7 + 2 + 2 + 2 + 6 + 65 + 5 = 666.

It is not a de Polignac number, because 21357172226655 - 2² = 21357172226651 is a prime.

It is a super-2 number, since 2×21357172226655² (a number of 27 digits) contains 22 as substring.

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21357172226651) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 79100637742 + ... + 79100638011.

It is an arithmetic number, because the mean of its divisors is an integer number (2373019136310).

Almost surely, 2^{21357172226655} is an apocalyptic number.

21357172226655 is a deficient number, since it is larger than the sum of its proper divisors (16611133954305).

21357172226655 is a wasteful number, since it uses less digits than its factorization.

21357172226655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158201275767 (or 158201275761 counting only the distinct ones).

The product of its digits is 10584000, while the sum is 54.

The spelling of 21357172226655 in words is "twenty-one trillion, three hundred fifty-seven billion, one hundred seventy-two million, two hundred twenty-six thousand, six hundred fifty-five".