1997521992 has 32 divisors (see below), whose sum is σ = 5548672800. Its totient is φ = 665840592.

The previous prime is 1997521991. The next prime is 1997522011. The reversal of 1997521992 is 2991257991.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (1997521991) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4623678 + ... + 4624109.

It is an arithmetic number, because the mean of its divisors is an integer number (173396025).

Almost surely, 2^1997521992 is an apocalyptic number.

1997521992 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1997521992 is an abundant number, since it is smaller than the sum of its proper divisors (3551150808).

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

1997521992 is a wasteful number, since it uses less digits than its factorization.

1997521992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9247802 (or 9247792 counting only the distinct ones).

The product of its digits is 918540, while the sum is 54.

The square root of 1997521992 is about 44693.6459913487. The cubic root of 1997521992 is about 1259.4004857685.

The spelling of 1997521992 in words is "one billion, nine hundred ninety-seven million, five hundred twenty-one thousand, nine hundred ninety-two".