21231645305 has 32 divisors (see below), whose sum is σ = 27926881920. Its totient is φ = 15399751680.

The previous prime is 21231645301. The next prime is 21231645307. The reversal of 21231645305 is 50354613212.

It is a happy number.

It is not a de Polignac number, because 21231645305 - 2² = 21231645301 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21231645301) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7710809 + ... + 7713561.

It is an arithmetic number, because the mean of its divisors is an integer number (872715060).

Almost surely, 2^21231645305 is an apocalyptic number.

It is an amenable number.

21231645305 is a deficient number, since it is larger than the sum of its proper divisors (6695236615).

21231645305 is a wasteful number, since it uses less digits than its factorization.

21231645305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4841.

The product of its (nonzero) digits is 21600, while the sum is 32.

The spelling of 21231645305 in words is "twenty-one billion, two hundred thirty-one million, six hundred forty-five thousand, three hundred five".