105780721 has 2 divisors, whose sum is σ = 105780722. Its totient is φ = 105780720.

The previous prime is 105780671. The next prime is 105780737. The reversal of 105780721 is 127087501.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 73290721 + 32490000 = 8561^2 + 5700^2 .

It is a cyclic number.

It is not a de Polignac number, because 105780721 - 2¹⁹ = 105256433 is a prime.

It is a super-2 number, since 2×105780721² = 22379121870559682, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (105780781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 52890360 + 52890361.

It is an arithmetic number, because the mean of its divisors is an integer number (52890361).

Almost surely, 2^105780721 is an apocalyptic number.

It is an amenable number.

105780721 is a deficient number, since it is larger than the sum of its proper divisors (1).

105780721 is an equidigital number, since it uses as much as digits as its factorization.

105780721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3920, while the sum is 31.

The square root of 105780721 is about 10284.9754982693. The cubic root of 105780721 is about 472.9357826485.

The spelling of 105780721 in words is "one hundred five million, seven hundred eighty thousand, seven hundred twenty-one".