66434551 has 4 divisors (see below), whose sum is σ = 67523704. Its totient is φ = 65345400.

The previous prime is 66434549. The next prime is 66434561. The reversal of 66434551 is 15543466.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15543466 = 2 ⋅7771733.

It is a cyclic number.

It is not a de Polignac number, because 66434551 - 2¹ = 66434549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66434561) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 544485 + ... + 544606.

It is an arithmetic number, because the mean of its divisors is an integer number (16880926).

Almost surely, 2^66434551 is an apocalyptic number.

66434551 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

66434551 is a deficient number, since it is larger than the sum of its proper divisors (1089153).

66434551 is a wasteful number, since it uses less digits than its factorization.

66434551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1089152.

The product of its digits is 43200, while the sum is 34.

The square root of 66434551 is about 8150.7392916226. The cubic root of 66434551 is about 405.0089943641.

The spelling of 66434551 in words is "sixty-six million, four hundred thirty-four thousand, five hundred fifty-one".