1990400397 has 16 divisors (see below), whose sum is σ = 2671468800. Its totient is φ = 1318162752.

The previous prime is 1990400371. The next prime is 1990400437. The reversal of 1990400397 is 7930040991.

It is not a de Polignac number, because 1990400397 - 2⁶ = 1990400333 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1990400597) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 286588 + ... + 293450.

It is an arithmetic number, because the mean of its divisors is an integer number (166966800).

Almost surely, 2^1990400397 is an apocalyptic number.

It is an amenable number.

1990400397 is a deficient number, since it is larger than the sum of its proper divisors (681068403).

1990400397 is a wasteful number, since it uses less digits than its factorization.

1990400397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7492.

The product of its (nonzero) digits is 61236, while the sum is 42.

The square root of 1990400397 is about 44613.9036288016. The cubic root of 1990400397 is about 1257.9020258211.

The spelling of 1990400397 in words is "one billion, nine hundred ninety million, four hundred thousand, three hundred ninety-seven".