1997635646 has 4 divisors (see below), whose sum is σ = 2996453472. Its totient is φ = 998817822.

The previous prime is 1997635613. The next prime is 1997635669. The reversal of 1997635646 is 6465367991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6465367991 = 71 ⋅91061521.

It is a junction number, because it is equal to n+sod(n) for n = 1997635591 and 1997635600.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499408910 + ... + 499408913.

It is an arithmetic number, because the mean of its divisors is an integer number (749113368).

Almost surely, 2^1997635646 is an apocalyptic number.

1997635646 is a deficient number, since it is larger than the sum of its proper divisors (998817826).

1997635646 is an equidigital number, since it uses as much as digits as its factorization.

1997635646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 998817825.

The product of its digits is 7348320, while the sum is 56.

The square root of 1997635646 is about 44694.9174515403. The cubic root of 1997635646 is about 1259.4243708936.

The spelling of 1997635646 in words is "one billion, nine hundred ninety-seven million, six hundred thirty-five thousand, six hundred forty-six".