21550355042 has 4 divisors (see below), whose sum is σ = 32325532566. Its totient is φ = 10775177520.

The previous prime is 21550355041. The next prime is 21550355051. The reversal of 21550355042 is 24055305512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 19610921521 + 1939433521 = 140039^2 + 44039^2 .

It is not an unprimeable number, because it can be changed into a prime (21550355041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5387588759 + ... + 5387588762.

Almost surely, 2^21550355042 is an apocalyptic number.

21550355042 is a deficient number, since it is larger than the sum of its proper divisors (10775177524).

21550355042 is a wasteful number, since it uses less digits than its factorization.

21550355042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10775177523.

The product of its (nonzero) digits is 30000, while the sum is 32.

The spelling of 21550355042 in words is "twenty-one billion, five hundred fifty million, three hundred fifty-five thousand, forty-two".