21266331401 has 4 divisors (see below), whose sum is σ = 24304378752. Its totient is φ = 18228284052.

The previous prime is 21266331389. The next prime is 21266331431. The reversal of 21266331401 is 10413366212.

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 21266331401 - 2⁶ = 21266331337 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21266331431) 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, 1519023665 + ... + 1519023678.

It is an arithmetic number, because the mean of its divisors is an integer number (6076094688).

Almost surely, 2^21266331401 is an apocalyptic number.

It is an amenable number.

21266331401 is a deficient number, since it is larger than the sum of its proper divisors (3038047351).

21266331401 is an equidigital number, since it uses as much as digits as its factorization.

21266331401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3038047350.

The product of its (nonzero) digits is 5184, while the sum is 29.

Adding to 21266331401 its reverse (10413366212), we get a palindrome (31679697613).

The spelling of 21266331401 in words is "twenty-one billion, two hundred sixty-six million, three hundred thirty-one thousand, four hundred one".