51530021 has 8 divisors (see below), whose sum is σ = 52436160. Its totient is φ = 50631328.

The previous prime is 51529991. The next prime is 51530053. The reversal of 51530021 is 12003515.

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-51530021 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 (51530321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13130 + ... + 16596.

It is an arithmetic number, because the mean of its divisors is an integer number (6554520).

Almost surely, 2^51530021 is an apocalyptic number.

It is an amenable number.

51530021 is a deficient number, since it is larger than the sum of its proper divisors (906139).

51530021 is a wasteful number, since it uses less digits than its factorization.

51530021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3723.

The product of its (nonzero) digits is 150, while the sum is 17.

The square root of 51530021 is about 7178.4414046505. The cubic root of 51530021 is about 372.1232224656.

Adding to 51530021 its reverse (12003515), we get a palindrome (63533536).

The spelling of 51530021 in words is "fifty-one million, five hundred thirty thousand, twenty-one".