1667015661 has 4 divisors (see below), whose sum is σ = 2222687552. Its totient is φ = 1111343772.

The previous prime is 1667015641. The next prime is 1667015743. The reversal of 1667015661 is 1665107661.

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 not a de Polignac number, because 1667015661 - 2⁷ = 1667015533 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 (1667015641) 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, 277835941 + ... + 277835946.

It is an arithmetic number, because the mean of its divisors is an integer number (555671888).

Almost surely, 2^1667015661 is an apocalyptic number.

It is an amenable number.

1667015661 is a deficient number, since it is larger than the sum of its proper divisors (555671891).

1667015661 is an equidigital number, since it uses as much as digits as its factorization.

1667015661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 555671890.

The product of its (nonzero) digits is 45360, while the sum is 39.

The square root of 1667015661 is about 40829.1031128532. The cubic root of 1667015661 is about 1185.7138514283.

The spelling of 1667015661 in words is "one billion, six hundred sixty-seven million, fifteen thousand, six hundred sixty-one".