123664551 has 4 divisors (see below), whose sum is σ = 164886072. Its totient is φ = 82443032.

The previous prime is 123664523. The next prime is 123664561. The reversal of 123664551 is 155466321.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 123664551 - 2¹³ = 123656359 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (123664561) 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, 20610756 + ... + 20610761.

It is an arithmetic number, because the mean of its divisors is an integer number (41221518).

Almost surely, 2^123664551 is an apocalyptic number.

123664551 is a deficient number, since it is larger than the sum of its proper divisors (41221521).

123664551 is an equidigital number, since it uses as much as digits as its factorization.

123664551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41221520.

The product of its digits is 21600, while the sum is 33.

The square root of 123664551 is about 11120.4564204892. The cubic root of 123664551 is about 498.2130223636.

The spelling of 123664551 in words is "one hundred twenty-three million, six hundred sixty-four thousand, five hundred fifty-one".