21154520660464 has 20 divisors (see below), whose sum is σ = 41447410566480. Its totient is φ = 10458414707840.

The previous prime is 21154520660461. The next prime is 21154520660467. The reversal of 21154520660464 is 46406602545112.

It is an interprime number because it is at equal distance from previous prime (21154520660461) and next prime (21154520660467).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21154520660461) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7427849932 + ... + 7427852779.

It is an arithmetic number, because the mean of its divisors is an integer number (2072370528324).

Almost surely, 2^{21154520660464} is an apocalyptic number.

It is an amenable number.

21154520660464 is a deficient number, since it is larger than the sum of its proper divisors (20292889906016).

21154520660464 is a wasteful number, since it uses less digits than its factorization.

21154520660464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14855702808 (or 14855702802 counting only the distinct ones).

The product of its (nonzero) digits is 1382400, while the sum is 46.

The spelling of 21154520660464 in words is "twenty-one trillion, one hundred fifty-four billion, five hundred twenty million, six hundred sixty thousand, four hundred sixty-four".