21121443541 has 8 divisors (see below), whose sum is σ = 23042919168. Its totient is φ = 19200192000.

The previous prime is 21121443527. The next prime is 21121443557. The reversal of 21121443541 is 14534412112.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21121443541 - 2²¹ = 21119346389 is a prime.

It is a super-2 number, since 2×21121443541² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

21121443541 is a modest number, since divided by 443541 gives 21121 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121443641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 186876 + ... + 277786.

It is an arithmetic number, because the mean of its divisors is an integer number (2880364896).

Almost surely, 2^21121443541 is an apocalyptic number.

It is an amenable number.

21121443541 is a deficient number, since it is larger than the sum of its proper divisors (1921475627).

21121443541 is a wasteful number, since it uses less digits than its factorization.

21121443541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112043.

The product of its digits is 3840, while the sum is 28.

Adding to 21121443541 its reverse (14534412112), we get a palindrome (35655855653).

The spelling of 21121443541 in words is "twenty-one billion, one hundred twenty-one million, four hundred forty-three thousand, five hundred forty-one".