21052545515 has 4 divisors (see below), whose sum is σ = 25263054624. Its totient is φ = 16842036408.

The previous prime is 21052545511. The next prime is 21052545533. The reversal of 21052545515 is 51554525012.

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 21052545515 - 2² = 21052545511 is a prime.

It is a super-2 number, since 2×21052545515² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21052545511) 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, 2105254547 + ... + 2105254556.

It is an arithmetic number, because the mean of its divisors is an integer number (6315763656).

Almost surely, 2^21052545515 is an apocalyptic number.

21052545515 is a deficient number, since it is larger than the sum of its proper divisors (4210509109).

21052545515 is an equidigital number, since it uses as much as digits as its factorization.

21052545515 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4210509108.

The product of its (nonzero) digits is 50000, while the sum is 35.

The spelling of 21052545515 in words is "twenty-one billion, fifty-two million, five hundred forty-five thousand, five hundred fifteen".