21620123154 has 64 divisors (see below), whose sum is σ = 54925516800. Its totient is φ = 6175235664.

The previous prime is 21620123153. The next prime is 21620123249. The reversal of 21620123154 is 45132102612.

21620123154 is a `hidden beast` number, since 2 + 1 + 620 + 1 + 2 + 31 + 5 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21620123153) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1553077 + ... + 1566935.

It is an arithmetic number, because the mean of its divisors is an integer number (858211200).

Almost surely, 2^21620123154 is an apocalyptic number.

21620123154 is an abundant number, since it is smaller than the sum of its proper divisors (33305393646).

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

21620123154 is a wasteful number, since it uses less digits than its factorization.

21620123154 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18004 (or 17998 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

Adding to 21620123154 its reverse (45132102612), we get a palindrome (66752225766).

The spelling of 21620123154 in words is "twenty-one billion, six hundred twenty million, one hundred twenty-three thousand, one hundred fifty-four".