21057121792 has 160 divisors (see below), whose sum is σ = 52364505600. Its totient is φ = 8253923328.

The previous prime is 21057121753. The next prime is 21057121847. The reversal of 21057121792 is 29712175012.

It is a happy number.

It is a super-3 number, since 3×21057121792³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1969453 + ... + 1980115.

It is an arithmetic number, because the mean of its divisors is an integer number (327278160).

Almost surely, 2^21057121792 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21057121792, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26182252800).

21057121792 is an abundant number, since it is smaller than the sum of its proper divisors (31307383808).

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

21057121792 is a wasteful number, since it uses less digits than its factorization.

21057121792 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10736 (or 10720 counting only the distinct ones).

The product of its (nonzero) digits is 17640, while the sum is 37.

The spelling of 21057121792 in words is "twenty-one billion, fifty-seven million, one hundred twenty-one thousand, seven hundred ninety-two".