976999981 has 4 divisors (see below), whose sum is σ = 977063932. Its totient is φ = 976936032.

The previous prime is 976999943. The next prime is 976999993. The reversal of 976999981 is 189999679.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 189999679 = 571 ⋅332749.

It can be written as a sum of positive squares in 2 ways, for example, as 777907881 + 199092100 = 27891^2 + 14110^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-976999981 is a prime.

It is a super-2 number, since 2×976999981² = 1909057925748000722, 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 (976999381) 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, 5881 + ... + 44593.

It is an arithmetic number, because the mean of its divisors is an integer number (244265983).

Almost surely, 2^976999981 is an apocalyptic number.

It is an amenable number.

976999981 is a deficient number, since it is larger than the sum of its proper divisors (63951).

976999981 is a wasteful number, since it uses less digits than its factorization.

976999981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63950.

The product of its digits is 19840464, while the sum is 67.

The square root of 976999981 is about 31256.9989122436. The cubic root of 976999981 is about 992.2737863600.

The spelling of 976999981 in words is "nine hundred seventy-six million, nine hundred ninety-nine thousand, nine hundred eighty-one".