13811781001021 has 32 divisors (see below), whose sum is σ = 15055928422400. Its totient is φ = 12629450508480.

The previous prime is 13811781000989. The next prime is 13811781001043. The reversal of 13811781001021 is 12010018711831.

It is a cyclic number.

It is not a de Polignac number, because 13811781001021 - 2⁵ = 13811781000989 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 (13811781001321) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14461720 + ... + 15387166.

It is an arithmetic number, because the mean of its divisors is an integer number (470497763200).

Almost surely, 2^{13811781001021} is an apocalyptic number.

It is an amenable number.

13811781001021 is a deficient number, since it is larger than the sum of its proper divisors (1244147421379).

13811781001021 is a wasteful number, since it uses less digits than its factorization.

13811781001021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 925769.

The product of its (nonzero) digits is 2688, while the sum is 34.

Adding to 13811781001021 its reverse (12010018711831), we get a palindrome (25821799712852).

The spelling of 13811781001021 in words is "thirteen trillion, eight hundred eleven billion, seven hundred eighty-one million, one thousand, twenty-one".