16901981 has 2 divisors, whose sum is σ = 16901982. Its totient is φ = 16901980.

The previous prime is 16901977. The next prime is 16902031. The reversal of 16901981 is 18910961.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9665881 + 7236100 = 3109^2 + 2690^2 .

It is a cyclic number.

It is not a de Polignac number, because 16901981 - 2² = 16901977 is a prime.

It is a super-2 number, since 2×16901981² = 571353923448722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16901921) 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, 8450990 + 8450991.

It is an arithmetic number, because the mean of its divisors is an integer number (8450991).

Almost surely, 2^16901981 is an apocalyptic number.

It is an amenable number.

16901981 is a deficient number, since it is larger than the sum of its proper divisors (1).

16901981 is an equidigital number, since it uses as much as digits as its factorization.

16901981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3888, while the sum is 35.

The square root of 16901981 is about 4111.2018923911. The cubic root of 16901981 is about 256.6330210202.

The spelling of 16901981 in words is "sixteen million, nine hundred one thousand, nine hundred eighty-one".