61066991 has 2 divisors, whose sum is σ = 61066992. Its totient is φ = 61066990.

The previous prime is 61066981. The next prime is 61067021. The reversal of 61066991 is 19966016.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 61066991 - 2²² = 56872687 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (61066981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30533495 + 30533496.

It is an arithmetic number, because the mean of its divisors is an integer number (30533496).

Almost surely, 2^61066991 is an apocalyptic number.

61066991 is a deficient number, since it is larger than the sum of its proper divisors (1).

61066991 is an equidigital number, since it uses as much as digits as its factorization.

61066991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17496, while the sum is 38.

The square root of 61066991 is about 7814.5371583991. The cubic root of 61066991 is about 393.7937693513.

The spelling of 61066991 in words is "sixty-one million, sixty-six thousand, nine hundred ninety-one".