1961661 has 16 divisors (see below), whose sum is σ = 2842560. Its totient is φ = 1196160.

The previous prime is 1961657. The next prime is 1961669. The reversal of 1961661 is 1661691.

It is a happy number.

It is not a de Polignac number, because 1961661 - 2² = 1961657 is a prime.

It is a super-2 number, since 2×1961661² = 7696227757842, which contains 22 as substring.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1961669) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6841 + ... + 7121.

It is an arithmetic number, because the mean of its divisors is an integer number (177660).

2^1961661 is an apocalyptic number.

It is an amenable number.

1961661 is a deficient number, since it is larger than the sum of its proper divisors (880899).

1961661 is a wasteful number, since it uses less digits than its factorization.

1961661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 476.

The product of its digits is 1944, while the sum is 30.

The square root of 1961661 is about 1400.5930886592. The cubic root of 1961661 is about 125.1818366884.

Adding to 1961661 its sum of digits (30), we get a palindrome (1961691).

The spelling of 1961661 in words is "one million, nine hundred sixty-one thousand, six hundred sixty-one".