21375651811 has 4 divisors (see below), whose sum is σ = 22633043112. Its totient is φ = 20118260512.

The previous prime is 21375651779. The next prime is 21375651821. The reversal of 21375651811 is 11815657312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21375651811 - 2⁵ = 21375651779 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21375651821) 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, 628695625 + ... + 628695658.

It is an arithmetic number, because the mean of its divisors is an integer number (5658260778).

Almost surely, 2^21375651811 is an apocalyptic number.

21375651811 is a deficient number, since it is larger than the sum of its proper divisors (1257391301).

21375651811 is a wasteful number, since it uses less digits than its factorization.

21375651811 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1257391300.

The product of its digits is 50400, while the sum is 40.

The spelling of 21375651811 in words is "twenty-one billion, three hundred seventy-five million, six hundred fifty-one thousand, eight hundred eleven".