21166552064 has 176 divisors, whose sum is σ = 51623702400. Its totient is φ = 8472231936.

The previous prime is 21166552061. The next prime is 21166552133. The reversal of 21166552064 is 46025566112.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21166552061) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9940952 + ... + 9943080.

Almost surely, 2^21166552064 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 21166552064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25811851200).

21166552064 is an abundant number, since it is smaller than the sum of its proper divisors (30457150336).

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

21166552064 is a wasteful number, since it uses less digits than its factorization.

21166552064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2248 (or 2230 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 38.

The spelling of 21166552064 in words is "twenty-one billion, one hundred sixty-six million, five hundred fifty-two thousand, sixty-four".