1961398685 has 12 divisors (see below), whose sum is σ = 2379126204. Its totient is φ = 1552170240.

The previous prime is 1961398667. The next prime is 1961398693. The reversal of 1961398685 is 5868931691.

It can be written as a sum of positive squares in 2 ways, for example, as 792647716 + 1168750969 = 28154^2 + 34187^2 .

It is not a de Polignac number, because 1961398685 - 2¹⁶ = 1961333149 is a prime.

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 1961398685.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 974330 + ... + 976340.

It is an arithmetic number, because the mean of its divisors is an integer number (198260517).

Almost surely, 2^1961398685 is an apocalyptic number.

It is an amenable number.

1961398685 is a deficient number, since it is larger than the sum of its proper divisors (417727519).

1961398685 is an frugal number, since it uses more digits than its factorization.

1961398685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4124 (or 2113 counting only the distinct ones).

The product of its digits is 2799360, while the sum is 56.

The square root of 1961398685 is about 44287.6809620915. The cubic root of 1961398685 is about 1251.7625663198.

The spelling of 1961398685 in words is "one billion, nine hundred sixty-one million, three hundred ninety-eight thousand, six hundred eighty-five".