10821515491 has 4 divisors (see below), whose sum is σ = 10839055032. Its totient is φ = 10803975952.

The previous prime is 10821515489. The next prime is 10821515521. The reversal of 10821515491 is 19451512801.

It is a happy number.

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 10821515491 - 2¹ = 10821515489 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 10821515491.

It is not an unprimeable number, because it can be changed into a prime (10821515591) 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, 8768845 + ... + 8770078.

It is an arithmetic number, because the mean of its divisors is an integer number (2709763758).

Almost surely, 2^10821515491 is an apocalyptic number.

10821515491 is a deficient number, since it is larger than the sum of its proper divisors (17539541).

10821515491 is an equidigital number, since it uses as much as digits as its factorization.

10821515491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17539540.

The product of its (nonzero) digits is 14400, while the sum is 37.

The spelling of 10821515491 in words is "ten billion, eight hundred twenty-one million, five hundred fifteen thousand, four hundred ninety-one".