172400035781 has 2 divisors, whose sum is σ = 172400035782. Its totient is φ = 172400035780.

The previous prime is 172400035771. The next prime is 172400035783. The reversal of 172400035781 is 187530004271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 163430998756 + 8969037025 = 404266^2 + 94705^2 .

It is a cyclic number.

It is not a de Polignac number, because 172400035781 - 2¹⁰ = 172400034757 is a prime.

It is a super-2 number, since 2×172400035781² (a number of 23 digits) contains 22 as substring.

Together with 172400035783, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (172400035783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86200017890 + 86200017891.

It is an arithmetic number, because the mean of its divisors is an integer number (86200017891).

Almost surely, 2^172400035781 is an apocalyptic number.

It is an amenable number.

172400035781 is a deficient number, since it is larger than the sum of its proper divisors (1).

172400035781 is an equidigital number, since it uses as much as digits as its factorization.

172400035781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 47040, while the sum is 38.

The spelling of 172400035781 in words is "one hundred seventy-two billion, four hundred million, thirty-five thousand, seven hundred eighty-one".