21357533978664 has 64 divisors (see below), whose sum is σ = 59055135565440. Its totient is φ = 6393939482880.

The previous prime is 21357533978663. The next prime is 21357533978707. The reversal of 21357533978664 is 46687933575312.

It is a super-2 number, since 2×21357533978664² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21357533978663) 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 15 ways as a sum of consecutive naturals, for example, 925037572 + ... + 925060659.

It is an arithmetic number, because the mean of its divisors is an integer number (922736493210).

Almost surely, 2^{21357533978664} is an apocalyptic number.

21357533978664 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21357533978664 is an abundant number, since it is smaller than the sum of its proper divisors (37697601586776).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21357533978664 is a wasteful number, since it uses less digits than its factorization.

21357533978664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1850098290 (or 1850098286 counting only the distinct ones).

The product of its digits is 685843200, while the sum is 69.

The spelling of 21357533978664 in words is "twenty-one trillion, three hundred fifty-seven billion, five hundred thirty-three million, nine hundred seventy-eight thousand, six hundred sixty-four".