1977584981 has 4 divisors (see below), whose sum is σ = 1977716364. Its totient is φ = 1977453600.

The previous prime is 1977584977. The next prime is 1977585013. The reversal of 1977584981 is 1894857791.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1000709956 + 976875025 = 31634^2 + 31255^2 .

It is a cyclic number.

It is not a de Polignac number, because 1977584981 - 2² = 1977584977 is a prime.

It is a super-2 number, since 2×1977584981² = 7821684714153540722, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1977584981.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1977584911) 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, 39680 + ... + 74361.

It is an arithmetic number, because the mean of its divisors is an integer number (494429091).

Almost surely, 2^1977584981 is an apocalyptic number.

It is an amenable number.

1977584981 is a deficient number, since it is larger than the sum of its proper divisors (131383).

1977584981 is a wasteful number, since it uses less digits than its factorization.

1977584981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131382.

The product of its digits is 5080320, while the sum is 59.

The square root of 1977584981 is about 44470.0458848425. The cubic root of 1977584981 is about 1255.1964964837.

The spelling of 1977584981 in words is "one billion, nine hundred seventy-seven million, five hundred eighty-four thousand, nine hundred eighty-one".