1666526487 has 4 divisors (see below), whose sum is σ = 2222035320. Its totient is φ = 1111017656.

The previous prime is 1666526483. The next prime is 1666526497. The reversal of 1666526487 is 7846256661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7846256661 = 3 ⋅2615418887.

It is a cyclic number.

It is not a de Polignac number, because 1666526487 - 2² = 1666526483 is a prime.

It is a super-2 number, since 2×1666526487² = 5554621063745122338, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666526483) 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, 277754412 + ... + 277754417.

It is an arithmetic number, because the mean of its divisors is an integer number (555508830).

Almost surely, 2^1666526487 is an apocalyptic number.

1666526487 is a deficient number, since it is larger than the sum of its proper divisors (555508833).

1666526487 is an equidigital number, since it uses as much as digits as its factorization.

1666526487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 555508832.

The product of its digits is 2903040, while the sum is 51.

The square root of 1666526487 is about 40823.1121670066. The cubic root of 1666526487 is about 1185.5978602902.

The spelling of 1666526487 in words is "one billion, six hundred sixty-six million, five hundred twenty-six thousand, four hundred eighty-seven".