1667406861 has 12 divisors (see below), whose sum is σ = 2426058492. Its totient is φ = 1103489856.

The previous prime is 1667406859. The next prime is 1667406863. The reversal of 1667406861 is 1686047661.

1667406861 is a `hidden beast` number, since 166 + 7 + 406 + 86 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (1667406859) and next prime (1667406863).

It can be written as a sum of positive squares in 2 ways, for example, as 517790025 + 1149616836 = 22755^2 + 33906^2 .

It is not a de Polignac number, because 1667406861 - 2¹ = 1667406859 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1667406863) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 674926 + ... + 677391.

It is an arithmetic number, because the mean of its divisors is an integer number (202171541).

Almost surely, 2^1667406861 is an apocalyptic number.

It is an amenable number.

1667406861 is a deficient number, since it is larger than the sum of its proper divisors (758651631).

1667406861 is a wasteful number, since it uses less digits than its factorization.

1667406861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1352460 (or 1352457 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The square root of 1667406861 is about 40833.8935322117. The cubic root of 1667406861 is about 1185.8065950039.

The spelling of 1667406861 in words is "one billion, six hundred sixty-seven million, four hundred six thousand, eight hundred sixty-one".