921623 has 4 divisors (see below), whose sum is σ = 941280. Its totient is φ = 901968.

The previous prime is 921611. The next prime is 921629. The reversal of 921623 is 326129.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 326129 = 101 ⋅3229.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-921623 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (921629) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9758 + ... + 9851.

It is an arithmetic number, because the mean of its divisors is an integer number (235320).

2⁹²¹⁶²³ is an apocalyptic number.

921623 is a deficient number, since it is larger than the sum of its proper divisors (19657).

921623 is a wasteful number, since it uses less digits than its factorization.

921623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19656.

The product of its digits is 648, while the sum is 23.

The square root of 921623 is about 960.0119790919. The cubic root of 921623 is about 97.3160414748.

Subtracting from 921623 its sum of digits (23), we obtain a square (921600 = 960²).

The spelling of 921623 in words is "nine hundred twenty-one thousand, six hundred twenty-three".