1971391748 has 12 divisors (see below), whose sum is σ = 3451321692. Its totient is φ = 985299840.

The previous prime is 1971391729. The next prime is 1971391769. The reversal of 1971391748 is 8471931791.

It can be written as a sum of positive squares in 2 ways, for example, as 74615044 + 1896776704 = 8638^2 + 43552^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1971391696 and 1971391705.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 87665 + ... + 107832.

It is an arithmetic number, because the mean of its divisors is an integer number (287610141).

Almost surely, 2^1971391748 is an apocalyptic number.

It is an amenable number.

1971391748 is a deficient number, since it is larger than the sum of its proper divisors (1479929944).

1971391748 is a wasteful number, since it uses less digits than its factorization.

1971391748 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198022 (or 198020 counting only the distinct ones).

The product of its digits is 381024, while the sum is 50.

The square root of 1971391748 is about 44400.3575210831. The cubic root of 1971391748 is about 1253.8848202696.

The spelling of 1971391748 in words is "one billion, nine hundred seventy-one million, three hundred ninety-one thousand, seven hundred forty-eight".