51572021 has 4 divisors (see below), whose sum is σ = 52545132. Its totient is φ = 50598912.

The previous prime is 51571963. The next prime is 51572041. The reversal of 51572021 is 12027515.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 17757796 + 33814225 = 4214^2 + 5815^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51572021 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 (51572041) 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, 486476 + ... + 486581.

It is an arithmetic number, because the mean of its divisors is an integer number (13136283).

Almost surely, 2^51572021 is an apocalyptic number.

It is an amenable number.

51572021 is a deficient number, since it is larger than the sum of its proper divisors (973111).

51572021 is an equidigital number, since it uses as much as digits as its factorization.

51572021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 973110.

The product of its (nonzero) digits is 700, while the sum is 23.

The square root of 51572021 is about 7181.3662349166. The cubic root of 51572021 is about 372.2242957864.

Adding to 51572021 its reverse (12027515), we get a palindrome (63599536).

The spelling of 51572021 in words is "fifty-one million, five hundred seventy-two thousand, twenty-one".