721590786225 has 135 divisors (see below), whose sum is σ = 1371567302523. Its totient is φ = 375042195360.

The previous prime is 721590786223. The next prime is 721590786233. The reversal of 721590786225 is 522687095127.

The square root of 721590786225 is 849465.

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

721590786225 is a `hidden beast` number, since 7 + 2 + 1 + 5 + 9 + 0 + 7 + 8 + 622 + 5 = 666.

It can be written as a sum of positive squares in only one way, i.e., 259772683041 + 461818103184 = 509679^2 + 679572^2 .

It is a tau number, because it is divible by the number of its divisors (135).

It is not a de Polignac number, because 721590786225 - 2¹ = 721590786223 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (721590786223) by changing a digit.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 1643714556 + ... + 1643714994.

Almost surely, 2^721590786225 is an apocalyptic number.

721590786225 is a gapful number since it is divisible by the number (75) formed by its first and last digit.

721590786225 is the 849465-th square number.

721590786225 is the 424733-rd centered octagonal number.

It is an amenable number.

721590786225 is a deficient number, since it is larger than the sum of its proper divisors (649976516298).

721590786225 is an frugal number, since it uses more digits than its factorization.

721590786225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 986 (or 490 counting only the distinct ones).

The product of its (nonzero) digits is 4233600, while the sum is 54.

The spelling of 721590786225 in words is "seven hundred twenty-one billion, five hundred ninety million, seven hundred eighty-six thousand, two hundred twenty-five".