66978151 has 4 divisors (see below), whose sum is σ = 67570992. Its totient is φ = 66385312.

The previous prime is 66978137. The next prime is 66978169. The reversal of 66978151 is 15187966.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15187966 = 2 ⋅7593983.

It is a cyclic number.

It is not a de Polignac number, because 66978151 - 2²³ = 58589543 is a prime.

It is a super-2 number, since 2×66978151² = 8972145422757602, 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 = 66978098 and 66978107.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66978101) 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, 296251 + ... + 296476.

It is an arithmetic number, because the mean of its divisors is an integer number (16892748).

Almost surely, 2^66978151 is an apocalyptic number.

66978151 is a deficient number, since it is larger than the sum of its proper divisors (592841).

66978151 is a wasteful number, since it uses less digits than its factorization.

66978151 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 592840.

The product of its digits is 90720, while the sum is 43.

The square root of 66978151 is about 8184.0180229518. The cubic root of 66978151 is about 406.1106556105.

The spelling of 66978151 in words is "sixty-six million, nine hundred seventy-eight thousand, one hundred fifty-one".