21112151565 has 16 divisors (see below), whose sum is σ = 33782558400. Its totient is φ = 11258775552.

The previous prime is 21112151521. The next prime is 21112151581. The reversal of 21112151565 is 56515121112.

It is not a de Polignac number, because 21112151565 - 2¹⁷ = 21112020493 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 120141 + ... + 238029.

It is an arithmetic number, because the mean of its divisors is an integer number (2111409900).

Almost surely, 2^21112151565 is an apocalyptic number.

It is an amenable number.

21112151565 is a deficient number, since it is larger than the sum of its proper divisors (12670406835).

21112151565 is a wasteful number, since it uses less digits than its factorization.

21112151565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 129836.

The product of its digits is 3000, while the sum is 30.

Adding to 21112151565 its reverse (56515121112), we get a palindrome (77627272677).

The spelling of 21112151565 in words is "twenty-one billion, one hundred twelve million, one hundred fifty-one thousand, five hundred sixty-five".