21167726660 has 12 divisors (see below), whose sum is σ = 44452226028. Its totient is φ = 8467090656.

The previous prime is 21167726641. The next prime is 21167726687. The reversal of 21167726660 is 6662776112.

It can be written as a sum of positive squares in 2 ways, for example, as 15048419584 + 6119307076 = 122672^2 + 78226^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 529193147 + ... + 529193186.

It is an arithmetic number, because the mean of its divisors is an integer number (3704352169).

Almost surely, 2^21167726660 is an apocalyptic number.

21167726660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21167726660 is an abundant number, since it is smaller than the sum of its proper divisors (23284499368).

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

21167726660 is a wasteful number, since it uses less digits than its factorization.

21167726660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1058386342 (or 1058386340 counting only the distinct ones).

The product of its (nonzero) digits is 254016, while the sum is 44.

The spelling of 21167726660 in words is "twenty-one billion, one hundred sixty-seven million, seven hundred twenty-six thousand, six hundred sixty".