66156551 has 2 divisors, whose sum is σ = 66156552. Its totient is φ = 66156550.

The previous prime is 66156547. The next prime is 66156557. The reversal of 66156551 is 15565166.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66156551 - 2² = 66156547 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66156557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33078275 + 33078276.

It is an arithmetic number, because the mean of its divisors is an integer number (33078276).

Almost surely, 2^66156551 is an apocalyptic number.

66156551 is a deficient number, since it is larger than the sum of its proper divisors (1).

66156551 is an equidigital number, since it uses as much as digits as its factorization.

66156551 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27000, while the sum is 35.

The square root of 66156551 is about 8133.6677458573. The cubic root of 66156551 is about 404.4432750948.

The spelling of 66156551 in words is "sixty-six million, one hundred fifty-six thousand, five hundred fifty-one".