21555031441 has 8 divisors (see below), whose sum is σ = 22708906400. Its totient is φ = 20403096480.

The previous prime is 21555031387. The next prime is 21555031447. The reversal of 21555031441 is 14413055512.

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 21555031441 - 2⁷ = 21555031313 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21555031447) 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, 462156 + ... + 506653.

It is an arithmetic number, because the mean of its divisors is an integer number (2838613300).

Almost surely, 2^21555031441 is an apocalyptic number.

It is an amenable number.

21555031441 is a deficient number, since it is larger than the sum of its proper divisors (1153874959).

21555031441 is a wasteful number, since it uses less digits than its factorization.

21555031441 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 969999.

The product of its (nonzero) digits is 12000, while the sum is 31.

Adding to 21555031441 its reverse (14413055512), we get a palindrome (35968086953).

The spelling of 21555031441 in words is "twenty-one billion, five hundred fifty-five million, thirty-one thousand, four hundred forty-one".