21165611340 has 48 divisors (see below), whose sum is σ = 59570810208. Its totient is φ = 5614915584.

The previous prime is 21165611309. The next prime is 21165611351. The reversal of 21165611340 is 4311656112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 21165611298 and 21165611307.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 902307 + ... + 925466.

It is an arithmetic number, because the mean of its divisors is an integer number (1241058546).

Almost surely, 2^21165611340 is an apocalyptic number.

21165611340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21165611340 is an abundant number, since it is smaller than the sum of its proper divisors (38405198868).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21165611340 is a wasteful number, since it uses less digits than its factorization.

21165611340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1827978 (or 1827976 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 30.

The spelling of 21165611340 in words is "twenty-one billion, one hundred sixty-five million, six hundred eleven thousand, three hundred forty".