1620778373 has 2 divisors, whose sum is σ = 1620778374. Its totient is φ = 1620778372.

The previous prime is 1620778333. The next prime is 1620778381. The reversal of 1620778373 is 3738770261.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 931348324 + 689430049 = 30518^2 + 26257^2 .

It is a cyclic number.

It is not a de Polignac number, because 1620778373 - 2⁶ = 1620778309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1620778333) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810389186 + 810389187.

It is an arithmetic number, because the mean of its divisors is an integer number (810389187).

Almost surely, 2^1620778373 is an apocalyptic number.

It is an amenable number.

1620778373 is a deficient number, since it is larger than the sum of its proper divisors (1).

1620778373 is an equidigital number, since it uses as much as digits as its factorization.

1620778373 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 296352, while the sum is 44.

The square root of 1620778373 is about 40258.8918501242. The cubic root of 1620778373 is about 1174.6483626815.

The spelling of 1620778373 in words is "one billion, six hundred twenty million, seven hundred seventy-eight thousand, three hundred seventy-three".