20440643541 has 4 divisors (see below), whose sum is σ = 27254191392. Its totient is φ = 13627095692.

The previous prime is 20440643539. The next prime is 20440643567. The reversal of 20440643541 is 14534604402.

It is a happy number.

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 20440643541 - 2¹ = 20440643539 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20440645541) 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, 3406773921 + ... + 3406773926.

It is an arithmetic number, because the mean of its divisors is an integer number (6813547848).

Almost surely, 2^20440643541 is an apocalyptic number.

It is an amenable number.

20440643541 is a deficient number, since it is larger than the sum of its proper divisors (6813547851).

20440643541 is an equidigital number, since it uses as much as digits as its factorization.

20440643541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6813547850.

The product of its (nonzero) digits is 46080, while the sum is 33.

The spelling of 20440643541 in words is "twenty billion, four hundred forty million, six hundred forty-three thousand, five hundred forty-one".