66969551 has 4 divisors (see below), whose sum is σ = 73057704. Its totient is φ = 60881400.

The previous prime is 66969541. The next prime is 66969569. The reversal of 66969551 is 15596966.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66969551 - 2¹⁰ = 66968527 is a prime.

It is a super-2 number, since 2×66969551² = 8969841522283202, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66969496 and 66969505.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66969541) 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, 3044060 + ... + 3044081.

It is an arithmetic number, because the mean of its divisors is an integer number (18264426).

Almost surely, 2^66969551 is an apocalyptic number.

66969551 is a deficient number, since it is larger than the sum of its proper divisors (6088153).

66969551 is a wasteful number, since it uses less digits than its factorization.

66969551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6088152.

The product of its digits is 437400, while the sum is 47.

The square root of 66969551 is about 8183.4925917972. The cubic root of 66969551 is about 406.0932733195.

The spelling of 66969551 in words is "sixty-six million, nine hundred sixty-nine thousand, five hundred fifty-one".