661402423 has 8 divisors (see below), whose sum is σ = 735144336. Its totient is φ = 589929600.

The previous prime is 661402387. The next prime is 661402451. The reversal of 661402423 is 324204166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661402423 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 661402391 and 661402400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661402223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 566658 + ... + 567823.

It is an arithmetic number, because the mean of its divisors is an integer number (91893042).

Almost surely, 2^661402423 is an apocalyptic number.

661402423 is a deficient number, since it is larger than the sum of its proper divisors (73741913).

661402423 is a wasteful number, since it uses less digits than its factorization.

661402423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1134545.

The product of its (nonzero) digits is 6912, while the sum is 28.

The square root of 661402423 is about 25717.7452938628. The cubic root of 661402423 is about 871.2750156085.

Adding to 661402423 its reverse (324204166), we get a palindrome (985606589).

It can be divided in two parts, 661402 and 423, that added together give a triangular number (661825 = T₁₁₅₀).

The spelling of 661402423 in words is "six hundred sixty-one million, four hundred two thousand, four hundred twenty-three".