21455123120 has 40 divisors (see below), whose sum is σ = 52051998816. Its totient is φ = 8208915968.

The previous prime is 21455123119. The next prime is 21455123149. The reversal of 21455123120 is 2132155412.

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 21455123120.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 5828357 + ... + 5832036.

Almost surely, 2^21455123120 is an apocalyptic number.

21455123120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21455123120 is an abundant number, since it is smaller than the sum of its proper divisors (30596875696).

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

21455123120 is a wasteful number, since it uses less digits than its factorization.

21455123120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11660429 (or 11660423 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 26.

Adding to 21455123120 its reverse (2132155412), we get a palindrome (23587278532).

The spelling of 21455123120 in words is "twenty-one billion, four hundred fifty-five million, one hundred twenty-three thousand, one hundred twenty".