9101981 has 4 divisors (see below), whose sum is σ = 10402272. Its totient is φ = 7801692.

The previous prime is 9101977. The next prime is 9101999. The reversal of 9101981 is 1891019.

9101981 is digitally balanced in base 2 and base 3, because in such bases it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1891019 = 13 ⋅145463.

It is a cyclic number.

It is not a de Polignac number, because 9101981 - 2² = 9101977 is a prime.

It is a super-2 number, since 2×9101981² = 165692116248722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9101921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 650135 + ... + 650148.

It is an arithmetic number, because the mean of its divisors is an integer number (2600568).

Almost surely, 2^9101981 is an apocalyptic number.

It is an amenable number.

9101981 is a deficient number, since it is larger than the sum of its proper divisors (1300291).

9101981 is a wasteful number, since it uses less digits than its factorization.

9101981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1300290.

The product of its (nonzero) digits is 648, while the sum is 29.

The square root of 9101981 is about 3016.9489554847. The cubic root of 9101981 is about 208.7910964065.

The spelling of 9101981 in words is "nine million, one hundred one thousand, nine hundred eighty-one".