109656721 has 2 divisors, whose sum is σ = 109656722. Its totient is φ = 109656720.

The previous prime is 109656713. The next prime is 109656739. The reversal of 109656721 is 127656901.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 71216721 + 38440000 = 8439^2 + 6200^2 .

It is an emirp because it is prime and its reverse (127656901) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 109656721 - 2³ = 109656713 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is not a weakly prime, because it can be changed into another prime (109656791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 54828360 + 54828361.

It is an arithmetic number, because the mean of its divisors is an integer number (54828361).

Almost surely, 2^109656721 is an apocalyptic number.

It is an amenable number.

109656721 is a deficient number, since it is larger than the sum of its proper divisors (1).

109656721 is an equidigital number, since it uses as much as digits as its factorization.

109656721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 22680, while the sum is 37.

The square root of 109656721 is about 10471.7105097496. The cubic root of 109656721 is about 478.6430439581.

The spelling of 109656721 in words is "one hundred nine million, six hundred fifty-six thousand, seven hundred twenty-one".