66213504 has 384 divisors, whose sum is σ = 251164800. Its totient is φ = 17031168.

The previous prime is 66213503. The next prime is 66213509. The reversal of 66213504 is 40531266.

66213504 is a `hidden beast` number, since 6 + 621 + 35 + 0 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a super-2 number, since 2×66213504² = 8768456223916032, which contains 22 as substring.

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 (66213503) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 2878837 + ... + 2878859.

It is an arithmetic number, because the mean of its divisors is an integer number (654075).

Almost surely, 2^66213504 is an apocalyptic number.

66213504 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66213504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125582400).

66213504 is an abundant number, since it is smaller than the sum of its proper divisors (184951296).

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

66213504 is a wasteful number, since it uses less digits than its factorization.

66213504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77 (or 52 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 66213504 is about 8137.1680577459. The cubic root of 66213504 is about 404.5593011508.

The spelling of 66213504 in words is "sixty-six million, two hundred thirteen thousand, five hundred four".