1225681816637 has 2 divisors, whose sum is σ = 1225681816638. Its totient is φ = 1225681816636.

The previous prime is 1225681816607. The next prime is 1225681816669. The reversal of 1225681816637 is 7366181865221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1110802170916 + 114879645721 = 1053946^2 + 338939^2 .

It is a cyclic number.

It is not a de Polignac number, because 1225681816637 - 2¹² = 1225681812541 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1225681816607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 612840908318 + 612840908319.

It is an arithmetic number, because the mean of its divisors is an integer number (612840908319).

Almost surely, 2^{1225681816637} is an apocalyptic number.

It is an amenable number.

1225681816637 is a deficient number, since it is larger than the sum of its proper divisors (1).

1225681816637 is an equidigital number, since it uses as much as digits as its factorization.

1225681816637 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5806080, while the sum is 56.

The spelling of 1225681816637 in words is "one trillion, two hundred twenty-five billion, six hundred eighty-one million, eight hundred sixteen thousand, six hundred thirty-seven".