661023 has 18 divisors (see below), whose sum is σ = 1051232. Its totient is φ = 399960.

The previous prime is 661019. The next prime is 661027. The reversal of 661023 is 320166.

It is a happy number.

661023 is a `hidden beast` number, since 661 + 0 + 2 + 3 = 666.

661023 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (661019) and next prime (661027).

It is not a de Polignac number, because 661023 - 2² = 661019 is a prime.

It is a hoax number, since the sum of its digits (18) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 660987 and 661005.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 661023.

It is not an unprimeable number, because it can be changed into a prime (661027) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 786 + ... + 1392.

2⁶⁶¹⁰²³ is an apocalyptic number.

661023 is a deficient number, since it is larger than the sum of its proper divisors (390209).

661023 is a wasteful number, since it uses less digits than its factorization.

661023 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 635 (or 621 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 661023 is about 813.0332096538. The cubic root of 661023 is about 87.1108377264.

Adding to 661023 its reverse (320166), we get a palindrome (981189).

It can be divided in two parts, 66 and 1023, that added together give a square (1089 = 33²).

The spelling of 661023 in words is "six hundred sixty-one thousand, twenty-three".