21123537315 has 16 divisors (see below), whose sum is σ = 33800388000. Its totient is φ = 11264977152.

The previous prime is 21123537313. The next prime is 21123537319. The reversal of 21123537315 is 51373532112.

It is not a de Polignac number, because 21123537315 - 2¹ = 21123537313 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21123537311) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 162471 + ... + 261999.

It is an arithmetic number, because the mean of its divisors is an integer number (2112524250).

Almost surely, 2^21123537315 is an apocalyptic number.

21123537315 is a deficient number, since it is larger than the sum of its proper divisors (12676850685).

21123537315 is a wasteful number, since it uses less digits than its factorization.

21123537315 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113686.

The product of its digits is 18900, while the sum is 33.

The spelling of 21123537315 in words is "twenty-one billion, one hundred twenty-three million, five hundred thirty-seven thousand, three hundred fifteen".