21544020401 has 8 divisors (see below), whose sum is σ = 21983280000. Its totient is φ = 21108924720.

The previous prime is 21544020359. The next prime is 21544020427. The reversal of 21544020401 is 10402044512.

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

It is a cyclic number.

It is not a de Polignac number, because 21544020401 - 2²² = 21539826097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21544020461) 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, 1030526 + ... + 1051223.

It is an arithmetic number, because the mean of its divisors is an integer number (2747910000).

Almost surely, 2^21544020401 is an apocalyptic number.

It is an amenable number.

21544020401 is a deficient number, since it is larger than the sum of its proper divisors (439259599).

21544020401 is a wasteful number, since it uses less digits than its factorization.

21544020401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2081959.

The product of its (nonzero) digits is 1280, while the sum is 23.

Adding to 21544020401 its reverse (10402044512), we get a palindrome (31946064913).

The spelling of 21544020401 in words is "twenty-one billion, five hundred forty-four million, twenty thousand, four hundred one".