2978725621 has 2 divisors, whose sum is σ = 2978725622. Its totient is φ = 2978725620.

The previous prime is 2978725619. The next prime is 2978725643. The reversal of 2978725621 is 1265278792.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2846222500 + 132503121 = 53350^2 + 11511^2 .

It is a cyclic number.

It is not a de Polignac number, because 2978725621 - 2¹ = 2978725619 is a prime.

Together with 2978725619, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2978720621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1489362810 + 1489362811.

It is an arithmetic number, because the mean of its divisors is an integer number (1489362811).

Almost surely, 2^2978725621 is an apocalyptic number.

It is an amenable number.

2978725621 is a deficient number, since it is larger than the sum of its proper divisors (1).

2978725621 is an equidigital number, since it uses as much as digits as its factorization.

2978725621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 846720, while the sum is 49.

The square root of 2978725621 is about 54577.7025991384. The cubic root of 2978725621 is about 1438.8322614105.

The spelling of 2978725621 in words is "two billion, nine hundred seventy-eight million, seven hundred twenty-five thousand, six hundred twenty-one".