21444020101511 has 4 divisors (see below), whose sum is σ = 24507451544592. Its totient is φ = 18380588658432.

The previous prime is 21444020101447. The next prime is 21444020101573. The reversal of 21444020101511 is 11510102044412.

It is a happy number.

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

It is not a de Polignac number, because 21444020101511 - 2⁶ = 21444020101447 is a prime.

It is a super-2 number, since 2×21444020101511² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21444020101591) 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, 1531715721530 + ... + 1531715721543.

It is an arithmetic number, because the mean of its divisors is an integer number (6126862886148).

Almost surely, 2^{21444020101511} is an apocalyptic number.

21444020101511 is a deficient number, since it is larger than the sum of its proper divisors (3063431443081).

21444020101511 is an equidigital number, since it uses as much as digits as its factorization.

21444020101511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3063431443080.

The product of its (nonzero) digits is 1280, while the sum is 26.

Adding to 21444020101511 its reverse (11510102044412), we get a palindrome (32954122145923).

The spelling of 21444020101511 in words is "twenty-one trillion, four hundred forty-four billion, twenty million, one hundred one thousand, five hundred eleven".