720439281 has 27 divisors (see below), whose sum is σ = 1090650379. Its totient is φ = 458229552.

The previous prime is 720439261. The next prime is 720439337. The reversal of 720439281 is 182934027.

The square root of 720439281 is 26841.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 170067681 + 550371600 = 13041^2 + 23460^2 .

It is not a de Polignac number, because 720439281 - 2⁹ = 720438769 is a prime.

It is a super-2 number, since 2×720439281² = 1038065515215593922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (720439211) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1851835 + ... + 1852223.

Almost surely, 2^720439281 is an apocalyptic number.

720439281 is the 26841-st square number.

720439281 is the 13421-st centered octagonal number.

It is an amenable number.

720439281 is a deficient number, since it is larger than the sum of its proper divisors (370211098).

720439281 is an equidigital number, since it uses as much as digits as its factorization.

720439281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 830 (or 415 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The cubic root of 720439281 is about 896.4631896576.

Multiplying 720439281 by its sum of digits (36), we get a square (25935814116 = 161046²).

The spelling of 720439281 in words is "seven hundred twenty million, four hundred thirty-nine thousand, two hundred eighty-one".