21154355442 has 80 divisors (see below), whose sum is σ = 51937459200. Its totient is φ = 6382294560.

The previous prime is 21154355441. The next prime is 21154355461. The reversal of 21154355442 is 24455345112.

21154355442 is a `hidden beast` number, since 2 + 11 + 54 + 3 + 554 + 42 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 21154355397 and 21154355406.

It is not an unprimeable number, because it can be changed into a prime (21154355441) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 382159 + ... + 433997.

It is an arithmetic number, because the mean of its divisors is an integer number (649218240).

Almost surely, 2^21154355442 is an apocalyptic number.

21154355442 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 21154355442, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25968729600).

21154355442 is an abundant number, since it is smaller than the sum of its proper divisors (30783103758).

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

21154355442 is a wasteful number, since it uses less digits than its factorization.

21154355442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52093 (or 52084 counting only the distinct ones).

The product of its digits is 96000, while the sum is 36.

The spelling of 21154355442 in words is "twenty-one billion, one hundred fifty-four million, three hundred fifty-five thousand, four hundred forty-two".