1967661 has 6 divisors (see below), whose sum is σ = 2842190. Its totient is φ = 1311768.

The previous prime is 1967657. The next prime is 1967671. The reversal of 1967661 is 1667691.

It can be written as a sum of positive squares in only one way, i.e., 1822500 + 145161 = 1350^2 + 381^2 .

It is not a de Polignac number, because 1967661 - 2² = 1967657 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 (1967671) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 109306 + ... + 109323.

2^1967661 is an apocalyptic number.

It is an amenable number.

1967661 is a deficient number, since it is larger than the sum of its proper divisors (874529).

1967661 is a wasteful number, since it uses less digits than its factorization.

1967661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218635 (or 218632 counting only the distinct ones).

The product of its digits is 13608, while the sum is 36.

The square root of 1967661 is about 1402.7334030385. The cubic root of 1967661 is about 125.3093351958.

It can be divided in two parts, 1967 and 661, that added together give a triangular number (2628 = T₇₂).

The spelling of 1967661 in words is "one million, nine hundred sixty-seven thousand, six hundred sixty-one".