126121565 has 4 divisors (see below), whose sum is σ = 151345884. Its totient is φ = 100897248.

The previous prime is 126121561. The next prime is 126121603. The reversal of 126121565 is 565121621.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 565121621 = 619 ⋅912959.

It can be written as a sum of positive squares in 2 ways, for example, as 60543961 + 65577604 = 7781^2 + 8098^2 .

It is a cyclic number.

It is not a de Polignac number, because 126121565 - 2² = 126121561 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (126121561) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12612152 + ... + 12612161.

It is an arithmetic number, because the mean of its divisors is an integer number (37836471).

Almost surely, 2^126121565 is an apocalyptic number.

It is an amenable number.

126121565 is a deficient number, since it is larger than the sum of its proper divisors (25224319).

126121565 is an equidigital number, since it uses as much as digits as its factorization.

126121565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25224318.

The product of its digits is 3600, while the sum is 29.

The square root of 126121565 is about 11230.3857903458. The cubic root of 126121565 is about 501.4909696001.

The spelling of 126121565 in words is "one hundred twenty-six million, one hundred twenty-one thousand, five hundred sixty-five".