1245709921 has 8 divisors (see below), whose sum is σ = 1287705600. Its totient is φ = 1203827520.

The previous prime is 1245709897. The next prime is 1245709973. The reversal of 1245709921 is 1299075421.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1245709921 - 2¹⁷ = 1245578849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1245709991) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5656 + ... + 50233.

It is an arithmetic number, because the mean of its divisors is an integer number (160963200).

Almost surely, 2^1245709921 is an apocalyptic number.

It is an amenable number.

1245709921 is a deficient number, since it is larger than the sum of its proper divisors (41995679).

1245709921 is an equidigital number, since it uses as much as digits as its factorization.

1245709921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56639.

The product of its (nonzero) digits is 45360, while the sum is 40.

The square root of 1245709921 is about 35294.6160341772. The cubic root of 1245709921 is about 1075.9835731405.

The spelling of 1245709921 in words is "one billion, two hundred forty-five million, seven hundred nine thousand, nine hundred twenty-one".