1985787700381 has 2 divisors, whose sum is σ = 1985787700382. Its totient is φ = 1985787700380.

The previous prime is 1985787700319. The next prime is 1985787700423. The reversal of 1985787700381 is 1830077875891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1049208927481 + 936578772900 = 1024309^2 + 967770^2 .

It is a cyclic number.

It is not a de Polignac number, because 1985787700381 - 2⁹ = 1985787699869 is a prime.

It is a super-2 number, since 2×1985787700381² (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 (1985787700081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 992893850190 + 992893850191.

It is an arithmetic number, because the mean of its divisors is an integer number (992893850191).

Almost surely, 2^{1985787700381} is an apocalyptic number.

It is an amenable number.

1985787700381 is a deficient number, since it is larger than the sum of its proper divisors (1).

1985787700381 is an equidigital number, since it uses as much as digits as its factorization.

1985787700381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23708160, while the sum is 64.

The spelling of 1985787700381 in words is "one trillion, nine hundred eighty-five billion, seven hundred eighty-seven million, seven hundred thousand, three hundred eighty-one".