997961040400 has 135 divisors (see below), whose sum is σ = 2419348879533. Its totient is φ = 395596080000.

The previous prime is 997961040331. The next prime is 997961040409. The reversal of 997961040400 is 4040169799.

The square root of 997961040400 is 998980.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 359265974544 + 638695065856 = 599388^2 + 799184^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (997961040409) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 3975940275 + ... + 3975940525.

Almost surely, 2^997961040400 is an apocalyptic number.

997961040400 is the 998980-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 997961040400

997961040400 is an abundant number, since it is smaller than the sum of its proper divisors (1421387839133).

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

997961040400 is an equidigital number, since it uses as much as digits as its factorization.

997961040400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 918 (or 457 counting only the distinct ones).

The product of its (nonzero) digits is 489888, while the sum is 49.

Multiplying 997961040400 by its sum of digits (49), we get a square (48900090979600 = 6992860²).

The spelling of 997961040400 in words is "nine hundred ninety-seven billion, nine hundred sixty-one million, forty thousand, four hundred".