52217821 has 2 divisors, whose sum is σ = 52217822. Its totient is φ = 52217820.

The previous prime is 52217771. The next prime is 52217831. The reversal of 52217821 is 12871225.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 37884025 + 14333796 = 6155^2 + 3786^2 .

It is a cyclic number.

It is not a de Polignac number, because 52217821 - 2⁹ = 52217309 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 52217821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (52217831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 26108910 + 26108911.

It is an arithmetic number, because the mean of its divisors is an integer number (26108911).

Almost surely, 2^52217821 is an apocalyptic number.

It is an amenable number.

52217821 is a deficient number, since it is larger than the sum of its proper divisors (1).

52217821 is an equidigital number, since it uses as much as digits as its factorization.

52217821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2240, while the sum is 28.

The square root of 52217821 is about 7226.1899366125. The cubic root of 52217821 is about 373.7715558982.

The spelling of 52217821 in words is "fifty-two million, two hundred seventeen thousand, eight hundred twenty-one".