21555271842 has 32 divisors (see below), whose sum is σ = 46619422080. Its totient is φ = 6604865280.

The previous prime is 21555271841. The next prime is 21555271861. The reversal of 21555271842 is 24817255512.

It is a junction number, because it is equal to n+sod(n) for n = 21555271794 and 21555271803.

It is not an unprimeable number, because it can be changed into a prime (21555271841) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 554542 + ... + 592137.

It is an arithmetic number, because the mean of its divisors is an integer number (1456856940).

Almost surely, 2^21555271842 is an apocalyptic number.

21555271842 is an abundant number, since it is smaller than the sum of its proper divisors (25064150238).

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

21555271842 is a wasteful number, since it uses less digits than its factorization.

21555271842 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1146938.

The product of its digits is 224000, while the sum is 42.

The spelling of 21555271842 in words is "twenty-one billion, five hundred fifty-five million, two hundred seventy-one thousand, eight hundred forty-two".