1245415721 has 8 divisors (see below), whose sum is σ = 1369334784. Its totient is φ = 1123279920.

The previous prime is 1245415709. The next prime is 1245415771. The reversal of 1245415721 is 1275145421.

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 1245415721 - 2⁶ = 1245415657 is a prime.

It is a super-2 number, since 2×1245415721² = 3102120636227899682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1245415771) 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, 444350 + ... + 447143.

It is an arithmetic number, because the mean of its divisors is an integer number (171166848).

Almost surely, 2^1245415721 is an apocalyptic number.

1245415721 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1245415721 is a deficient number, since it is larger than the sum of its proper divisors (123919063).

1245415721 is a wasteful number, since it uses less digits than its factorization.

1245415721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 891631.

The product of its digits is 11200, while the sum is 32.

The square root of 1245415721 is about 35290.4480135914. The cubic root of 1245415721 is about 1075.8988612598.

The spelling of 1245415721 in words is "one billion, two hundred forty-five million, four hundred fifteen thousand, seven hundred twenty-one".