21006440941 has 4 divisors (see below), whose sum is σ = 21166795584. Its totient is φ = 20846086300.

The previous prime is 21006440927. The next prime is 21006440947. The reversal of 21006440941 is 14904460012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21006440941 - 2⁵ = 21006440909 is a prime.

It is a super-2 number, since 2×21006440941² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21006440947) 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, 80177125 + ... + 80177386.

It is an arithmetic number, because the mean of its divisors is an integer number (5291698896).

Almost surely, 2^21006440941 is an apocalyptic number.

It is an amenable number.

21006440941 is a deficient number, since it is larger than the sum of its proper divisors (160354643).

21006440941 is a wasteful number, since it uses less digits than its factorization.

21006440941 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160354642.

The product of its (nonzero) digits is 6912, while the sum is 31.

The spelling of 21006440941 in words is "twenty-one billion, six million, four hundred forty thousand, nine hundred forty-one".