221970389 has 2 divisors, whose sum is σ = 221970390. Its totient is φ = 221970388.

The previous prime is 221970347. The next prime is 221970403. The reversal of 221970389 is 983079122.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 212868100 + 9102289 = 14590^2 + 3017^2 .

It is a cyclic number.

It is not a de Polignac number, because 221970389 - 2¹⁶ = 221904853 is a prime.

It is a super-2 number, since 2×221970389² = 98541707185622642, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221972389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110985194 + 110985195.

It is an arithmetic number, because the mean of its divisors is an integer number (110985195).

Almost surely, 2^221970389 is an apocalyptic number.

It is an amenable number.

221970389 is a deficient number, since it is larger than the sum of its proper divisors (1).

221970389 is an equidigital number, since it uses as much as digits as its factorization.

221970389 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54432, while the sum is 41.

The square root of 221970389 is about 14898.6707125166. The cubic root of 221970389 is about 605.4779721246.

The spelling of 221970389 in words is "two hundred twenty-one million, nine hundred seventy thousand, three hundred eighty-nine".