1650561 has 12 divisors (see below), whose sum is σ = 2419536. Its totient is φ = 1000120.

The previous prime is 1650557. The next prime is 1650563.

1650561 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1650561 - 2² = 1650557 is a prime.

It is a super-2 number, since 2×1650561² = 5448703229442, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

1650561 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1650563) 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, 1911 + ... + 2636.

It is an arithmetic number, because the mean of its divisors is an integer number (201628).

2^1650561 is an apocalyptic number.

1650561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1650561 is a deficient number, since it is larger than the sum of its proper divisors (768975).

1650561 is a wasteful number, since it uses less digits than its factorization.

1650561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4572 (or 4561 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 24.

The square root of 1650561 is about 1284.7416082621. The cubic root of 1650561 is about 118.1799657411.

It can be divided in two parts, 1650 and 561, that added together give a triangular number (2211 = T₆₆).

The spelling of 1650561 in words is "one million, six hundred fifty thousand, five hundred sixty-one".