21090000265 has 8 divisors (see below), whose sum is σ = 25308785088. Its totient is φ = 16871477040.

The previous prime is 21090000257. The next prime is 21090000277. The reversal of 21090000265 is 56200009012.

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

It is not a de Polignac number, because 21090000265 - 2³ = 21090000257 is a prime.

It is a super-2 number, since 2×21090000265² (a number of 21 digits) contains 22 as substring.

It is a Duffinian 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 7 ways as a sum of consecutive naturals, for example, 252124 + ... + 325186.

It is an arithmetic number, because the mean of its divisors is an integer number (3163598136).

Almost surely, 2^21090000265 is an apocalyptic number.

It is an amenable number.

21090000265 is a deficient number, since it is larger than the sum of its proper divisors (4218784823).

21090000265 is an equidigital number, since it uses as much as digits as its factorization.

21090000265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130799.

The product of its (nonzero) digits is 1080, while the sum is 25.

Adding to 21090000265 its reverse (56200009012), we get a palindrome (77290009277).

The spelling of 21090000265 in words is "twenty-one billion, ninety million, two hundred sixty-five", and thus it is an aban number.