21273955830 has 80 divisors (see below), whose sum is σ = 57386745504. Its totient is φ = 5654862720.

The previous prime is 21273955799. The next prime is 21273955831. The reversal of 21273955830 is 3855937212.

21273955830 is a `hidden beast` number, since 21 + 2 + 73 + 9 + 558 + 3 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21273955831) by changing a digit.

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 39 ways as a sum of consecutive naturals, for example, 211575 + ... + 295485.

Almost surely, 2^21273955830 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21273955830, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28693372752).

21273955830 is an abundant number, since it is smaller than the sum of its proper divisors (36112789674).

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

21273955830 is a wasteful number, since it uses less digits than its factorization.

21273955830 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84243 (or 84234 counting only the distinct ones).

The product of its (nonzero) digits is 453600, while the sum is 45.

The spelling of 21273955830 in words is "twenty-one billion, two hundred seventy-three million, nine hundred fifty-five thousand, eight hundred thirty".