1638236407061 has 2 divisors, whose sum is σ = 1638236407062. Its totient is φ = 1638236407060.

The previous prime is 1638236407039. The next prime is 1638236407097. The reversal of 1638236407061 is 1607046328361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1076418700036 + 561817707025 = 1037506^2 + 749545^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1638236407061 is a prime.

It is a super-5 number, since 5×1638236407061⁵ (a number of 62 digits) contains 55555 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1638236406997 and 1638236407015.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1638236407021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 819118203530 + 819118203531.

It is an arithmetic number, because the mean of its divisors is an integer number (819118203531).

Almost surely, 2^{1638236407061} is an apocalyptic number.

It is an amenable number.

1638236407061 is a deficient number, since it is larger than the sum of its proper divisors (1).

1638236407061 is an equidigital number, since it uses as much as digits as its factorization.

1638236407061 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 870912, while the sum is 47.

The spelling of 1638236407061 in words is "one trillion, six hundred thirty-eight billion, two hundred thirty-six million, four hundred seven thousand, sixty-one".