1997008640 has 72 divisors (see below), whose sum is σ = 5218356528. Its totient is φ = 726179840.

The previous prime is 1997008639. The next prime is 1997008669. The reversal of 1997008640 is 468007991.

It is a Harshad number since it is a multiple of its sum of digits (44).

It is a junction number, because it is equal to n+sod(n) for n = 1997008591 and 1997008600.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56837 + ... + 84996.

It is an arithmetic number, because the mean of its divisors is an integer number (72477174).

Almost surely, 2^1997008640 is an apocalyptic number.

1997008640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1997008640 is an abundant number, since it is smaller than the sum of its proper divisors (3221347888).

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

1997008640 is a wasteful number, since it uses less digits than its factorization.

1997008640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141865 (or 141851 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 44.

The square root of 1997008640 is about 44687.9026135709. The cubic root of 1997008640 is about 1259.2925902272.

The spelling of 1997008640 in words is "one billion, nine hundred ninety-seven million, eight thousand, six hundred forty".