21221071051015 has 16 divisors (see below), whose sum is σ = 28676450267136. Its totient is φ = 14935651178400.

The previous prime is 21221071051013. The next prime is 21221071051027. The reversal of 21221071051015 is 51015017012212.

It is not a de Polignac number, because 21221071051015 - 2¹ = 21221071051013 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221071051013) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6223186287 + ... + 6223189696.

It is an arithmetic number, because the mean of its divisors is an integer number (1792278141696).

Almost surely, 2^{21221071051015} is an apocalyptic number.

21221071051015 is a deficient number, since it is larger than the sum of its proper divisors (7455379216121).

21221071051015 is a wasteful number, since it uses less digits than its factorization.

21221071051015 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12446376030.

The product of its (nonzero) digits is 1400, while the sum is 28.

Adding to 21221071051015 its reverse (51015017012212), we get a palindrome (72236088063227).

The spelling of 21221071051015 in words is "twenty-one trillion, two hundred twenty-one billion, seventy-one million, fifty-one thousand, fifteen".