21545038401 has 4 divisors (see below), whose sum is σ = 28726717872. Its totient is φ = 14363358932.

The previous prime is 21545038367. The next prime is 21545038433. The reversal of 21545038401 is 10483054512.

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 21545038401 - 2¹³ = 21545030209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21545038481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3590839731 + ... + 3590839736.

It is an arithmetic number, because the mean of its divisors is an integer number (7181679468).

Almost surely, 2^21545038401 is an apocalyptic number.

It is an amenable number.

21545038401 is a deficient number, since it is larger than the sum of its proper divisors (7181679471).

21545038401 is an equidigital number, since it uses as much as digits as its factorization.

21545038401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7181679470.

The product of its (nonzero) digits is 19200, while the sum is 33.

The spelling of 21545038401 in words is "twenty-one billion, five hundred forty-five million, thirty-eight thousand, four hundred one".