21253773843 has 8 divisors (see below), whose sum is σ = 31487072400. Its totient is φ = 14169182544.

The previous prime is 21253773839. The next prime is 21253773917. The reversal of 21253773843 is 34837735212.

It is a happy number.

21253773843 is a `hidden beast` number, since 2 + 1 + 2 + 537 + 73 + 8 + 43 = 666.

It is not a de Polignac number, because 21253773843 - 2² = 21253773839 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21253771843) 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, 393588378 + ... + 393588431.

It is an arithmetic number, because the mean of its divisors is an integer number (3935884050).

Almost surely, 2^21253773843 is an apocalyptic number.

21253773843 is a deficient number, since it is larger than the sum of its proper divisors (10233298557).

21253773843 is an equidigital number, since it uses as much as digits as its factorization.

21253773843 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 787176818 (or 787176812 counting only the distinct ones).

The product of its digits is 846720, while the sum is 45.

The spelling of 21253773843 in words is "twenty-one billion, two hundred fifty-three million, seven hundred seventy-three thousand, eight hundred forty-three".