1820377670549 has 2 divisors, whose sum is σ = 1820377670550. Its totient is φ = 1820377670548.

The previous prime is 1820377670443. The next prime is 1820377670623. The reversal of 1820377670549 is 9450767730281.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1759185753649 + 61191916900 = 1326343^2 + 247370^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1820377670549 is a prime.

It is a super-2 number, since 2×1820377670549² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1820377670249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 910188835274 + 910188835275.

It is an arithmetic number, because the mean of its divisors is an integer number (910188835275).

It is a 1-persistent number, because it is pandigital, but 2⋅1820377670549 = 3640755341098 is not.

Almost surely, 2^{1820377670549} is an apocalyptic number.

It is an amenable number.

1820377670549 is a deficient number, since it is larger than the sum of its proper divisors (1).

1820377670549 is an equidigital number, since it uses as much as digits as its factorization.

1820377670549 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17781120, while the sum is 59.

The spelling of 1820377670549 in words is "one trillion, eight hundred twenty billion, three hundred seventy-seven million, six hundred seventy thousand, five hundred forty-nine".