21261702271620 has 48 divisors (see below), whose sum is σ = 59551482005568. Its totient is φ = 5668004830080.

The previous prime is 21261702271571. The next prime is 21261702271633. The reversal of 21261702271620 is 2617220716212.

It is a happy number.

It is a super-3 number, since 3×21261702271620³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

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, 55508874 + ... + 55890593.

It is an arithmetic number, because the mean of its divisors is an integer number (1240655875116).

Almost surely, 2^{21261702271620} is an apocalyptic number.

21261702271620 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21261702271620 is an abundant number, since it is smaller than the sum of its proper divisors (38289779733948).

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

21261702271620 is a wasteful number, since it uses less digits than its factorization.

21261702271620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111402660 (or 111402658 counting only the distinct ones).

The product of its (nonzero) digits is 56448, while the sum is 39.

Adding to 21261702271620 its reverse (2617220716212), we get a palindrome (23878922987832).

The spelling of 21261702271620 in words is "twenty-one trillion, two hundred sixty-one billion, seven hundred two million, two hundred seventy-one thousand, six hundred twenty".