66782151421 has 4 divisors (see below), whose sum is σ = 66890039200. Its totient is φ = 66674263644.

The previous prime is 66782151361. The next prime is 66782151439. The reversal of 66782151421 is 12415128766.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66782151421 - 2¹³ = 66782143229 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 (66782151451) 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, 53942961 + ... + 53944198.

It is an arithmetic number, because the mean of its divisors is an integer number (16722509800).

Almost surely, 2^66782151421 is an apocalyptic number.

It is an amenable number.

66782151421 is a deficient number, since it is larger than the sum of its proper divisors (107887779).

66782151421 is a wasteful number, since it uses less digits than its factorization.

66782151421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107887778.

The product of its digits is 161280, while the sum is 43.

The spelling of 66782151421 in words is "sixty-six billion, seven hundred eighty-two million, one hundred fifty-one thousand, four hundred twenty-one".