21255611655212 has 24 divisors (see below), whose sum is σ = 40805592730560. Its totient is φ = 9607666006160.

The previous prime is 21255611655181. The next prime is 21255611655221.

It is a happy number.

21255611655212 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1349383418 + ... + 1349399169.

It is an arithmetic number, because the mean of its divisors is an integer number (1700233030440).

Almost surely, 2^{21255611655212} is an apocalyptic number.

21255611655212 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21255611655212 is a deficient number, since it is larger than the sum of its proper divisors (19549981075348).

21255611655212 is a wasteful number, since it uses less digits than its factorization.

21255611655212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2698782781 (or 2698782779 counting only the distinct ones).

The product of its digits is 360000, while the sum is 44.

The spelling of 21255611655212 in words is "twenty-one trillion, two hundred fifty-five billion, six hundred eleven million, six hundred fifty-five thousand, two hundred twelve".