21001221001199 has 4 divisors (see below), whose sum is σ = 22236586942464. Its totient is φ = 19765855059936.

The previous prime is 21001221001169. The next prime is 21001221001207. The reversal of 21001221001199 is 99110012210012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21001221001199 - 2²⁴ = 21001204223983 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001221001169) 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, 617682970607 + ... + 617682970640.

It is an arithmetic number, because the mean of its divisors is an integer number (5559146735616).

Almost surely, 2^{21001221001199} is an apocalyptic number.

21001221001199 is a deficient number, since it is larger than the sum of its proper divisors (1235365941265).

21001221001199 is a wasteful number, since it uses less digits than its factorization.

21001221001199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1235365941264.

The product of its (nonzero) digits is 648, while the sum is 29.

The spelling of 21001221001199 in words is "twenty-one trillion, one billion, two hundred twenty-one million, one thousand, one hundred ninety-nine".