66527721 has 24 divisors (see below), whose sum is σ = 108937920. Its totient is φ = 38784096.

The previous prime is 66527719. The next prime is 66527723. The reversal of 66527721 is 12772566.

66527721 is a `hidden beast` number, since 66 + 527 + 72 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (66527719) and next prime (66527723).

It is not a de Polignac number, because 66527721 - 2¹ = 66527719 is a prime.

It is a super-2 number, since 2×66527721² = 8851875322907682, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66527723) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12741 + ... + 17186.

It is an arithmetic number, because the mean of its divisors is an integer number (4539080).

Almost surely, 2^66527721 is an apocalyptic number.

It is an amenable number.

66527721 is a deficient number, since it is larger than the sum of its proper divisors (42410199).

66527721 is a wasteful number, since it uses less digits than its factorization.

66527721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29965 (or 29962 counting only the distinct ones).

The product of its digits is 35280, while the sum is 36.

The square root of 66527721 is about 8156.4527216186. The cubic root of 66527721 is about 405.1982385703.

The spelling of 66527721 in words is "sixty-six million, five hundred twenty-seven thousand, seven hundred twenty-one".