21531200154 has 16 divisors (see below), whose sum is σ = 43252105248. Its totient is φ = 7145449232.

The previous prime is 21531200149. The next prime is 21531200183. The reversal of 21531200154 is 45100213512.

It is a happy number.

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, 7902897 + ... + 7905620.

It is an arithmetic number, because the mean of its divisors is an integer number (2703256578).

Almost surely, 2^21531200154 is an apocalyptic number.

21531200154 is an abundant number, since it is smaller than the sum of its proper divisors (21720905094).

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

21531200154 is a wasteful number, since it uses less digits than its factorization.

21531200154 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15808749.

The product of its (nonzero) digits is 1200, while the sum is 24.

Adding to 21531200154 its reverse (45100213512), we get a palindrome (66631413666).

The spelling of 21531200154 in words is "twenty-one billion, five hundred thirty-one million, two hundred thousand, one hundred fifty-four".