21001167663798 has 32 divisors (see below), whose sum is σ = 48096976792320. Its totient is φ = 5988545137440.

The previous prime is 21001167663781. The next prime is 21001167663799. The reversal of 21001167663798 is 89736676110012.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001167663799) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 491165068 + ... + 491207823.

It is an arithmetic number, because the mean of its divisors is an integer number (1503030524760).

Almost surely, 2^{21001167663798} is an apocalyptic number.

21001167663798 is an abundant number, since it is smaller than the sum of its proper divisors (27095809128522).

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

21001167663798 is a wasteful number, since it uses less digits than its factorization.

21001167663798 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 982373412.

The product of its (nonzero) digits is 4572288, while the sum is 57.

The spelling of 21001167663798 in words is "twenty-one trillion, one billion, one hundred sixty-seven million, six hundred sixty-three thousand, seven hundred ninety-eight".