1640961 has 27 divisors (see below), whose sum is σ = 2803203. Its totient is φ = 922320.

The previous prime is 1640953. The next prime is 1640971. The reversal of 1640961 is 1690461.

1640961 = 50² + 51² + ... + 171².

The square root of 1640961 is 1281.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 53361 + 1587600 = 231^2 + 1260^2 .

It is not a de Polignac number, because 1640961 - 2³ = 1640953 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1640941) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 26871 + ... + 26931.

2^1640961 is an apocalyptic number.

1640961 is the 1281-st square number.

1640961 is the 641-st centered octagonal number.

It is an amenable number.

1640961 is a deficient number, since it is larger than the sum of its proper divisors (1162242).

1640961 is an equidigital number, since it uses as much as digits as its factorization.

1640961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142 (or 71 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The cubic root of 1640961 is about 117.9504004894.

Multiplying 1640961 by its product of nonzero digits (1296), we get a square (2126685456 = 46116²).

It can be divided in two parts, 1640 and 961, that added together give a square (2601 = 51²).

The spelling of 1640961 in words is "one million, six hundred forty thousand, nine hundred sixty-one".