21651579759498 has 128 divisors (see below), whose sum is σ = 52155533574144. Its totient is φ = 5926764211200.

The previous prime is 21651579759421. The next prime is 21651579759517. The reversal of 21651579759498 is 89495797515612.

It is a Harshad number since it is a multiple of its sum of digits (78).

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4357158 + ... + 7892273.

It is an arithmetic number, because the mean of its divisors is an integer number (407465106048).

Almost surely, 2^{21651579759498} is an apocalyptic number.

21651579759498 is an abundant number, since it is smaller than the sum of its proper divisors (30503953814646).

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

21651579759498 is a wasteful number, since it uses less digits than its factorization.

21651579759498 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12249540.

The product of its digits is 1714608000, while the sum is 78.

The spelling of 21651579759498 in words is "twenty-one trillion, six hundred fifty-one billion, five hundred seventy-nine million, seven hundred fifty-nine thousand, four hundred ninety-eight".