21123134154 has 192 divisors, whose sum is σ = 50490760320. Its totient is φ = 6610222080.

The previous prime is 21123134147. The next prime is 21123134167. The reversal of 21123134154 is 45143132112.

21123134154 is a `hidden beast` number, since 2 + 11 + 231 + 3 + 415 + 4 = 666.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 76256664 + ... + 76256940.

It is an arithmetic number, because the mean of its divisors is an integer number (262972710).

Almost surely, 2^21123134154 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21123134154, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25245380160).

21123134154 is an abundant number, since it is smaller than the sum of its proper divisors (29367626166).

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

21123134154 is a wasteful number, since it uses less digits than its factorization.

21123134154 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 467 (or 455 counting only the distinct ones).

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

Adding to 21123134154 its reverse (45143132112), we get a palindrome (66266266266).

The spelling of 21123134154 in words is "twenty-one billion, one hundred twenty-three million, one hundred thirty-four thousand, one hundred fifty-four".