21195519073 has 4 divisors (see below), whose sum is σ = 21195829908. Its totient is φ = 21195208240.

The previous prime is 21195519047. The next prime is 21195519083. The reversal of 21195519073 is 37091559112.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 11264001424 + 9931517649 = 106132^2 + 99657^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21195519073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21195519013) 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, 3886 + ... + 205927.

It is an arithmetic number, because the mean of its divisors is an integer number (5298957477).

Almost surely, 2^21195519073 is an apocalyptic number.

It is an amenable number.

21195519073 is a deficient number, since it is larger than the sum of its proper divisors (310835).

21195519073 is a wasteful number, since it uses less digits than its factorization.

21195519073 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 310834.

The product of its (nonzero) digits is 85050, while the sum is 43.

The spelling of 21195519073 in words is "twenty-one billion, one hundred ninety-five million, five hundred nineteen thousand, seventy-three".