61221389 has 2 divisors, whose sum is σ = 61221390. Its totient is φ = 61221388.

The previous prime is 61221371. The next prime is 61221443. The reversal of 61221389 is 98312216.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 60684100 + 537289 = 7790^2 + 733^2 .

It is a cyclic number.

It is not a de Polignac number, because 61221389 - 2¹² = 61217293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61221889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30610694 + 30610695.

It is an arithmetic number, because the mean of its divisors is an integer number (30610695).

Almost surely, 2^61221389 is an apocalyptic number.

It is an amenable number.

61221389 is a deficient number, since it is larger than the sum of its proper divisors (1).

61221389 is an equidigital number, since it uses as much as digits as its factorization.

61221389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5184, while the sum is 32.

The square root of 61221389 is about 7824.4098179991. The cubic root of 61221389 is about 394.1253713043.

The spelling of 61221389 in words is "sixty-one million, two hundred twenty-one thousand, three hundred eighty-nine".