21046021015 has 4 divisors (see below), whose sum is σ = 25255225224. Its totient is φ = 16836816808.

The previous prime is 21046020971. The next prime is 21046021021. The reversal of 21046021015 is 51012064012.

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 21046021015 - 2⁷ = 21046020887 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2104602097 + ... + 2104602106.

It is an arithmetic number, because the mean of its divisors is an integer number (6313806306).

Almost surely, 2^21046021015 is an apocalyptic number.

21046021015 is a deficient number, since it is larger than the sum of its proper divisors (4209204209).

21046021015 is an equidigital number, since it uses as much as digits as its factorization.

21046021015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4209204208.

The product of its (nonzero) digits is 480, while the sum is 22.

Adding to 21046021015 its reverse (51012064012), we get a palindrome (72058085027).

The spelling of 21046021015 in words is "twenty-one billion, forty-six million, twenty-one thousand, fifteen".