997720007 has 2 divisors, whose sum is σ = 997720008. Its totient is φ = 997720006.

The previous prime is 997719991. The next prime is 997720043. The reversal of 997720007 is 700027799.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 997720007 - 2⁴ = 997719991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (997720307) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 498860003 + 498860004.

It is an arithmetic number, because the mean of its divisors is an integer number (498860004).

Almost surely, 2^997720007 is an apocalyptic number.

997720007 is a deficient number, since it is larger than the sum of its proper divisors (1).

997720007 is an equidigital number, since it uses as much as digits as its factorization.

997720007 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 55566, while the sum is 41.

The square root of 997720007 is about 31586.7061752250. The cubic root of 997720007 is about 999.2394240041.

The spelling of 997720007 in words is "nine hundred ninety-seven million, seven hundred twenty thousand, seven".