2157381641 has 2 divisors, whose sum is σ = 2157381642. Its totient is φ = 2157381640.

The previous prime is 2157381637. The next prime is 2157381679. The reversal of 2157381641 is 1461837512.

It is an a-pointer prime, because the next prime (2157381679) can be obtained adding 2157381641 to its sum of digits (38).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1947015625 + 210366016 = 44125^2 + 14504^2 .

It is a cyclic number.

It is not a de Polignac number, because 2157381641 - 2² = 2157381637 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 2157381595 and 2157381604.

It is not a weakly prime, because it can be changed into another prime (2157381341) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1078690820 + 1078690821.

It is an arithmetic number, because the mean of its divisors is an integer number (1078690821).

Almost surely, 2^2157381641 is an apocalyptic number.

It is an amenable number.

2157381641 is a deficient number, since it is larger than the sum of its proper divisors (1).

2157381641 is an equidigital number, since it uses as much as digits as its factorization.

2157381641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 40320, while the sum is 38.

The square root of 2157381641 is about 46447.6225548736. The cubic root of 2157381641 is about 1292.1382802805.

The spelling of 2157381641 in words is "two billion, one hundred fifty-seven million, three hundred eighty-one thousand, six hundred forty-one".