720146561 has 4 divisors (see below), whose sum is σ = 720316500. Its totient is φ = 719976624.

The previous prime is 720146543. The next prime is 720146579. The reversal of 720146561 is 165641027.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (720146543) and next prime (720146579).

It can be written as a sum of positive squares in 2 ways, for example, as 142945936 + 577200625 = 11956^2 + 24025^2 .

It is a cyclic number.

It is not a de Polignac number, because 720146561 - 2¹⁰ = 720145537 is a prime.

It is a super-2 number, since 2×720146561² = 1037222138640253442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (720146501) 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, 78446 + ... + 87143.

It is an arithmetic number, because the mean of its divisors is an integer number (180079125).

Almost surely, 2^720146561 is an apocalyptic number.

It is an amenable number.

720146561 is a deficient number, since it is larger than the sum of its proper divisors (169939).

720146561 is a wasteful number, since it uses less digits than its factorization.

720146561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169938.

The product of its (nonzero) digits is 10080, while the sum is 32.

The square root of 720146561 is about 26835.5465940234. The cubic root of 720146561 is about 896.3417599226.

Adding to 720146561 its reverse (165641027), we get a palindrome (885787588).

The spelling of 720146561 in words is "seven hundred twenty million, one hundred forty-six thousand, five hundred sixty-one".