21501100265 has 8 divisors (see below), whose sum is σ = 25802921088. Its totient is φ = 17199813040.

The previous prime is 21501100259. The next prime is 21501100267. The reversal of 21501100265 is 56200110512.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21501100265 - 2¹⁶ = 21501034729 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21501100265.

It is not an unprimeable number, because it can be changed into a prime (21501100267) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 38627 + ... + 210936.

It is an arithmetic number, because the mean of its divisors is an integer number (3225365136).

Almost surely, 2^21501100265 is an apocalyptic number.

It is an amenable number.

21501100265 is a deficient number, since it is larger than the sum of its proper divisors (4301820823).

21501100265 is a wasteful number, since it uses less digits than its factorization.

21501100265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266799.

The product of its (nonzero) digits is 600, while the sum is 23.

Adding to 21501100265 its reverse (56200110512), we get a palindrome (77701210777).

The spelling of 21501100265 in words is "twenty-one billion, five hundred one million, one hundred thousand, two hundred sixty-five".