46991981 has 2 divisors, whose sum is σ = 46991982. Its totient is φ = 46991980.

The previous prime is 46991957. The next prime is 46991993. The reversal of 46991981 is 18919964.

46991981 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 37319881 + 9672100 = 6109^2 + 3110^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-46991981 is a prime.

It is a super-2 number, since 2×46991981² = 4416492556608722, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (46990981) 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, 23495990 + 23495991.

It is an arithmetic number, because the mean of its divisors is an integer number (23495991).

Almost surely, 2^46991981 is an apocalyptic number.

It is an amenable number.

46991981 is a deficient number, since it is larger than the sum of its proper divisors (1).

46991981 is an equidigital number, since it uses as much as digits as its factorization.

46991981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 139968, while the sum is 47.

The square root of 46991981 is about 6855.0697297693. The cubic root of 46991981 is about 360.8620826080.

The spelling of 46991981 in words is "forty-six million, nine hundred ninety-one thousand, nine hundred eighty-one".