1961391523 has 32 divisors (see below), whose sum is σ = 2457302400. Its totient is φ = 1533362688.

The previous prime is 1961391491. The next prime is 1961391529. The reversal of 1961391523 is 3251931691.

It is not a de Polignac number, because 1961391523 - 2⁵ = 1961391491 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1961391529) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1368015 + ... + 1369447.

It is an arithmetic number, because the mean of its divisors is an integer number (76790700).

Almost surely, 2^1961391523 is an apocalyptic number.

1961391523 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

1961391523 is a deficient number, since it is larger than the sum of its proper divisors (495910877).

1961391523 is an equidigital number, since it uses as much as digits as its factorization.

1961391523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1568 (or 1542 counting only the distinct ones).

The product of its digits is 43740, while the sum is 40.

The square root of 1961391523 is about 44287.6001043181. The cubic root of 1961391523 is about 1251.7610427244.

The spelling of 1961391523 in words is "one billion, nine hundred sixty-one million, three hundred ninety-one thousand, five hundred twenty-three".