1961981971 has 32 divisors (see below), whose sum is σ = 2193408000. Its totient is φ = 1747643040.

The previous prime is 1961981963. The next prime is 1961981977. The reversal of 1961981971 is 1791891691.

It is a cyclic number.

It is not a de Polignac number, because 1961981971 - 2³ = 1961981963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1961981977) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3275130 + ... + 3275728.

It is an arithmetic number, because the mean of its divisors is an integer number (68544000).

Almost surely, 2^1961981971 is an apocalyptic number.

1961981971 is a deficient number, since it is larger than the sum of its proper divisors (231426029).

1961981971 is a wasteful number, since it uses less digits than its factorization.

1961981971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 799.

The product of its digits is 244944, while the sum is 52.

The square root of 1961981971 is about 44294.2656672396. The cubic root of 1961981971 is about 1251.8866381911.

The spelling of 1961981971 in words is "one billion, nine hundred sixty-one million, nine hundred eighty-one thousand, nine hundred seventy-one".