1015720001 has 4 divisors (see below), whose sum is σ = 1015787604. Its totient is φ = 1015652400.

The previous prime is 1015719959. The next prime is 1015720003. The reversal of 1015720001 is 1000275101.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 874680625 + 141039376 = 29575^2 + 11876^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1015720001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1015720003) 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, 11 + ... + 45071.

It is an arithmetic number, because the mean of its divisors is an integer number (253946901).

Almost surely, 2^1015720001 is an apocalyptic number.

It is an amenable number.

1015720001 is a deficient number, since it is larger than the sum of its proper divisors (67603).

1015720001 is an equidigital number, since it uses as much as digits as its factorization.

1015720001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67602.

The product of its (nonzero) digits is 70, while the sum is 17.

The square root of 1015720001 is about 31870.3624234178. The cubic root of 1015720001 is about 1005.2127800418.

Adding to 1015720001 its reverse (1000275101), we get a palindrome (2015995102).

Subtracting from 1015720001 its reverse (1000275101), we obtain a square (15444900 = 3930²).

The spelling of 1015720001 in words is "one billion, fifteen million, seven hundred twenty thousand, one".