991430056 has 8 divisors (see below), whose sum is σ = 1858931370. Its totient is φ = 495715024.

The previous prime is 991430053. The next prime is 991430071. The reversal of 991430056 is 650034199.

It can be written as a sum of positive squares in only one way, i.e., 990360900 + 1069156 = 31470^2 + 1034^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is a junction number, because it is equal to n+sod(n) for n = 991429997 and 991430024.

It is not an unprimeable number, because it can be changed into a prime (991430053) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61964371 + ... + 61964386.

Almost surely, 2^991430056 is an apocalyptic number.

991430056 is the 16831-st centered heptagonal number.

It is an amenable number.

991430056 is a deficient number, since it is larger than the sum of its proper divisors (867501314).

991430056 is a wasteful number, since it uses less digits than its factorization.

991430056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123928763 (or 123928759 counting only the distinct ones).

The product of its (nonzero) digits is 29160, while the sum is 37.

The square root of 991430056 is about 31486.9823260344. The cubic root of 991430056 is about 997.1351524863.

The spelling of 991430056 in words is "nine hundred ninety-one million, four hundred thirty thousand, fifty-six".