997643951 has 4 divisors (see below), whose sum is σ = 998049192. Its totient is φ = 997238712.

The previous prime is 997643947. The next prime is 997643957. The reversal of 997643951 is 159346799.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 159346799 = 197 ⋅808867.

It is a cyclic number.

It is not a de Polignac number, because 997643951 - 2² = 997643947 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 997643893 and 997643902.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (997643957) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 198905 + ... + 203858.

It is an arithmetic number, because the mean of its divisors is an integer number (249512298).

Almost surely, 2^997643951 is an apocalyptic number.

997643951 is a deficient number, since it is larger than the sum of its proper divisors (405241).

997643951 is a wasteful number, since it uses less digits than its factorization.

997643951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 405240.

The product of its digits is 1837080, while the sum is 53.

The square root of 997643951 is about 31585.5022280793. The cubic root of 997643951 is about 999.2140327507.

The spelling of 997643951 in words is "nine hundred ninety-seven million, six hundred forty-three thousand, nine hundred fifty-one".