1997304921 has 18 divisors (see below), whose sum is σ = 2981075370. Its totient is φ = 1288578240.

The previous prime is 1997304917. The next prime is 1997304923. The reversal of 1997304921 is 1294037991.

1997304921 is a `hidden beast` number, since 1 + 99 + 73 + 0 + 492 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1992729600 + 4575321 = 44640^2 + 2139^2 .

It is not a de Polignac number, because 1997304921 - 2² = 1997304917 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1997304923) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 106816 + ... + 124113.

Almost surely, 2^1997304921 is an apocalyptic number.

It is an amenable number.

1997304921 is a deficient number, since it is larger than the sum of its proper divisors (983770449).

1997304921 is a wasteful number, since it uses less digits than its factorization.

1997304921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 230997 (or 230963 counting only the distinct ones).

The product of its (nonzero) digits is 122472, while the sum is 45.

The square root of 1997304921 is about 44691.2174929258. The cubic root of 1997304921 is about 1259.3548643723.

The spelling of 1997304921 in words is "one billion, nine hundred ninety-seven million, three hundred four thousand, nine hundred twenty-one".