65999421 has 16 divisors (see below), whose sum is σ = 99859200. Its totient is φ = 43062624.

The previous prime is 65999411. The next prime is 65999429. The reversal of 65999421 is 12499956.

It is not a de Polignac number, because 65999421 - 2¹⁵ = 65966653 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65999429) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24736 + ... + 27273.

It is an arithmetic number, because the mean of its divisors is an integer number (6241200).

Almost surely, 2^65999421 is an apocalyptic number.

It is an amenable number.

65999421 is a deficient number, since it is larger than the sum of its proper divisors (33859779).

65999421 is a wasteful number, since it uses less digits than its factorization.

65999421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52065 (or 52059 counting only the distinct ones).

The product of its digits is 174960, while the sum is 45.

The square root of 65999421 is about 8124.0027695712. The cubic root of 65999421 is about 404.1228203022.

Subtracting from 65999421 its sum of digits (45), we obtain a square (65999376 = 8124²).

The spelling of 65999421 in words is "sixty-five million, nine hundred ninety-nine thousand, four hundred twenty-one".