1661650 has 24 divisors (see below), whose sum is σ = 3124800. Its totient is φ = 657360.

The previous prime is 1661641. The next prime is 1661659. The reversal of 1661650 is 561661.

1661650 = T₁₃₀ + T₁₃₁ + ... + T₂₂₉.

It is an interprime number because it is at equal distance from previous prime (1661641) and next prime (1661659).

It is a super-2 number, since 2×1661650² = 5522161445000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is not an unprimeable number, because it can be changed into a prime (1661659) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8251 + ... + 8449.

It is an arithmetic number, because the mean of its divisors is an integer number (130200).

2^1661650 is an apocalyptic number.

1661650 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1661650 is a deficient number, since it is larger than the sum of its proper divisors (1463150).

1661650 is a wasteful number, since it uses less digits than its factorization.

1661650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 378 (or 373 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 1661650 is about 1289.0500378185. The cubic root of 1661650 is about 118.4440322743. Note that the first 3 decimals are identical.

1661650 divided by its sum of digits (25) gives a palindrome (66466).

The spelling of 1661650 in words is "one million, six hundred sixty-one thousand, six hundred fifty".