997707720 has 128 divisors (see below), whose sum is σ = 3136573440. Its totient is φ = 253566720.

The previous prime is 997707703. The next prime is 997707721. The reversal of 997707720 is 27707799.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 997707720.

It is not an unprimeable number, because it can be changed into a prime (997707721) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 247239 + ... + 251241.

It is an arithmetic number, because the mean of its divisors is an integer number (24504480).

Almost surely, 2^997707720 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 997707720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1568286720).

997707720 is an abundant number, since it is smaller than the sum of its proper divisors (2138865720).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

997707720 is a wasteful number, since it uses less digits than its factorization.

997707720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4115 (or 4111 counting only the distinct ones).

The product of its (nonzero) digits is 388962, while the sum is 48.

The square root of 997707720 is about 31586.5116782465. The cubic root of 997707720 is about 999.2353220834.

The spelling of 997707720 in words is "nine hundred ninety-seven million, seven hundred seven thousand, seven hundred twenty".