1961859401 has 2 divisors, whose sum is σ = 1961859402. Its totient is φ = 1961859400.

The previous prime is 1961859371. The next prime is 1961859407. The reversal of 1961859401 is 1049581691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1137308176 + 824551225 = 33724^2 + 28715^2 .

It is a cyclic number.

It is not a de Polignac number, because 1961859401 - 2⁶ = 1961859337 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1961859407) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 980929700 + 980929701.

It is an arithmetic number, because the mean of its divisors is an integer number (980929701).

Almost surely, 2^1961859401 is an apocalyptic number.

It is an amenable number.

1961859401 is a deficient number, since it is larger than the sum of its proper divisors (1).

1961859401 is an equidigital number, since it uses as much as digits as its factorization.

1961859401 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 77760, while the sum is 44.

The square root of 1961859401 is about 44292.8820579560. The cubic root of 1961859401 is about 1251.8605681349.

The spelling of 1961859401 in words is "one billion, nine hundred sixty-one million, eight hundred fifty-nine thousand, four hundred one".