21558147206 has 4 divisors (see below), whose sum is σ = 32337220812. Its totient is φ = 10779073602.

The previous prime is 21558147187. The next prime is 21558147209. The reversal of 21558147206 is 60274185512.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21558147209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5389536800 + ... + 5389536803.

It is an arithmetic number, because the mean of its divisors is an integer number (8084305203).

Almost surely, 2^21558147206 is an apocalyptic number.

21558147206 is a deficient number, since it is larger than the sum of its proper divisors (10779073606).

21558147206 is a wasteful number, since it uses less digits than its factorization.

21558147206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10779073605.

The product of its (nonzero) digits is 134400, while the sum is 41.

The spelling of 21558147206 in words is "twenty-one billion, five hundred fifty-eight million, one hundred forty-seven thousand, two hundred six".