21693027278521 has 8 divisors (see below), whose sum is σ = 21775188909320. Its totient is φ = 21610947526272.

The previous prime is 21693027278497. The next prime is 21693027278539. The reversal of 21693027278521 is 12587272039612.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 279271028521 + 21413756250000 = 528461^2 + 4627500^2 .

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 21693027278521 - 2⁷ = 21693027278393 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21693027278551) 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, 19938726 + ... + 20998543.

It is an arithmetic number, because the mean of its divisors is an integer number (2721898613665).

Almost surely, 2^{21693027278521} is an apocalyptic number.

It is an amenable number.

21693027278521 is a deficient number, since it is larger than the sum of its proper divisors (82161630799).

21693027278521 is a wasteful number, since it uses less digits than its factorization.

21693027278521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40939275.

The product of its (nonzero) digits is 5080320, while the sum is 55.

The spelling of 21693027278521 in words is "twenty-one trillion, six hundred ninety-three billion, twenty-seven million, two hundred seventy-eight thousand, five hundred twenty-one".