215221973 has 2 divisors, whose sum is σ = 215221974. Its totient is φ = 215221972.

The previous prime is 215221943. The next prime is 215222003. The reversal of 215221973 is 379122512.

It is a balanced prime because it is at equal distance from previous prime (215221943) and next prime (215222003).

It can be written as a sum of positive squares in only one way, i.e., 149255089 + 65966884 = 12217^2 + 8122^2 .

It is a cyclic number.

It is not a de Polignac number, because 215221973 - 2¹⁴ = 215205589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (215221943) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107610986 + 107610987.

It is an arithmetic number, because the mean of its divisors is an integer number (107610987).

Almost surely, 2^215221973 is an apocalyptic number.

It is an amenable number.

215221973 is a deficient number, since it is larger than the sum of its proper divisors (1).

215221973 is an equidigital number, since it uses as much as digits as its factorization.

215221973 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7560, while the sum is 32.

The square root of 215221973 is about 14670.4455624224. The cubic root of 215221973 is about 599.2787379455.

The spelling of 215221973 in words is "two hundred fifteen million, two hundred twenty-one thousand, nine hundred seventy-three".