720477721 has 2 divisors, whose sum is σ = 720477722. Its totient is φ = 720477720.

The previous prime is 720477673. The next prime is 720477749. The reversal of 720477721 is 127774027.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 684345600 + 36132121 = 26160^2 + 6011^2 .

It is a cyclic number.

It is not a de Polignac number, because 720477721 - 2¹¹ = 720475673 is a prime.

It is equal to p_37257535 and since 720477721 and 37257535 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (720477761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360238860 + 360238861.

It is an arithmetic number, because the mean of its divisors is an integer number (360238861).

Almost surely, 2^720477721 is an apocalyptic number.

It is an amenable number.

720477721 is a deficient number, since it is larger than the sum of its proper divisors (1).

720477721 is an equidigital number, since it uses as much as digits as its factorization.

720477721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 38416, while the sum is 37.

The square root of 720477721 is about 26841.7160591494. The cubic root of 720477721 is about 896.4791333710.

The spelling of 720477721 in words is "seven hundred twenty million, four hundred seventy-seven thousand, seven hundred twenty-one".