106651981 has 2 divisors, whose sum is σ = 106651982. Its totient is φ = 106651980.

The previous prime is 106651967. The next prime is 106651991. The reversal of 106651981 is 189156601.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 94887081 + 11764900 = 9741^2 + 3430^2 .

It is an emirp because it is prime and its reverse (189156601) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 106651981 - 2⁹ = 106651469 is a prime.

It is a super-2 number, since 2×106651981² = 22749290102448722, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 106651981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (106651991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 53325990 + 53325991.

It is an arithmetic number, because the mean of its divisors is an integer number (53325991).

Almost surely, 2^106651981 is an apocalyptic number.

It is an amenable number.

106651981 is a deficient number, since it is larger than the sum of its proper divisors (1).

106651981 is an equidigital number, since it uses as much as digits as its factorization.

106651981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12960, while the sum is 37.

The square root of 106651981 is about 10327.2445986333. The cubic root of 106651981 is about 474.2306748708.

The spelling of 106651981 in words is "one hundred six million, six hundred fifty-one thousand, nine hundred eighty-one".