124721981 has 2 divisors, whose sum is σ = 124721982. Its totient is φ = 124721980.

The previous prime is 124721977. The next prime is 124722007. The reversal of 124721981 is 189127421.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 78943225 + 45778756 = 8885^2 + 6766^2 .

It is a cyclic number.

It is not a de Polignac number, because 124721981 - 2² = 124721977 is a prime.

It is a super-2 number, since 2×124721981² = 31111145089128722, 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 (124721941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 62360990 + 62360991.

It is an arithmetic number, because the mean of its divisors is an integer number (62360991).

Almost surely, 2^124721981 is an apocalyptic number.

It is an amenable number.

124721981 is a deficient number, since it is larger than the sum of its proper divisors (1).

124721981 is an equidigital number, since it uses as much as digits as its factorization.

124721981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8064, while the sum is 35.

The square root of 124721981 is about 11167.8995787032. The cubic root of 124721981 is about 499.6290328348.

The spelling of 124721981 in words is "one hundred twenty-four million, seven hundred twenty-one thousand, nine hundred eighty-one".