99770981 has 4 divisors (see below), whose sum is σ = 102467532. Its totient is φ = 97074432.

The previous prime is 99770971. The next prime is 99771029. The reversal of 99770981 is 18907799.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18907799 = 31 ⋅609929.

It can be written as a sum of positive squares in 2 ways, for example, as 87590881 + 12180100 = 9359^2 + 3490^2 .

It is a cyclic number.

It is not a de Polignac number, because 99770981 - 2¹⁴ = 99754597 is a prime.

It is a super-2 number, since 2×99770981² = 19908497299404722, 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 (99770921) 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, 1348220 + ... + 1348293.

It is an arithmetic number, because the mean of its divisors is an integer number (25616883).

Almost surely, 2^99770981 is an apocalyptic number.

It is an amenable number.

99770981 is a deficient number, since it is larger than the sum of its proper divisors (2696551).

99770981 is a wasteful number, since it uses less digits than its factorization.

99770981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2696550.

The product of its (nonzero) digits is 285768, while the sum is 50.

The square root of 99770981 is about 9988.5424862690. The cubic root of 99770981 is about 463.8042751723.

The spelling of 99770981 in words is "ninety-nine million, seven hundred seventy thousand, nine hundred eighty-one".