165861920407 has 2 divisors, whose sum is σ = 165861920408. Its totient is φ = 165861920406.

The previous prime is 165861920377. The next prime is 165861920429. The reversal of 165861920407 is 704029168561.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 165861920407 - 2¹¹ = 165861918359 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165861920437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82930960203 + 82930960204.

It is an arithmetic number, because the mean of its divisors is an integer number (82930960204).

Almost surely, 2^165861920407 is an apocalyptic number.

165861920407 is a deficient number, since it is larger than the sum of its proper divisors (1).

165861920407 is an equidigital number, since it uses as much as digits as its factorization.

165861920407 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 725760, while the sum is 49.

The spelling of 165861920407 in words is "one hundred sixty-five billion, eight hundred sixty-one million, nine hundred twenty thousand, four hundred seven".