1971539455 has 4 divisors (see below), whose sum is σ = 2365847352. Its totient is φ = 1577231560.

The previous prime is 1971539447. The next prime is 1971539533. The reversal of 1971539455 is 5549351791.

It is a happy number.

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

It is not a de Polignac number, because 1971539455 - 2³ = 1971539447 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1971539399 and 1971539408.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 197153941 + ... + 197153950.

It is an arithmetic number, because the mean of its divisors is an integer number (591461838).

Almost surely, 2^1971539455 is an apocalyptic number.

1971539455 is a deficient number, since it is larger than the sum of its proper divisors (394307897).

1971539455 is an equidigital number, since it uses as much as digits as its factorization.

1971539455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 394307896.

The product of its digits is 850500, while the sum is 49.

The square root of 1971539455 is about 44402.0208436508. The cubic root of 1971539455 is about 1253.9161353613.

The spelling of 1971539455 in words is "one billion, nine hundred seventy-one million, five hundred thirty-nine thousand, four hundred fifty-five".