1631320445 has 4 divisors (see below), whose sum is σ = 1957584540. Its totient is φ = 1305056352.

The previous prime is 1631320399. The next prime is 1631320447. The reversal of 1631320445 is 5440231361.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5440231361 = 67 ⋅81197483.

It can be written as a sum of positive squares in 2 ways, for example, as 1281854809 + 349465636 = 35803^2 + 18694^2 .

It is a cyclic number.

It is not a de Polignac number, because 1631320445 - 2⁶ = 1631320381 is a prime.

It is a super-2 number, since 2×1631320445² = 5322412788549996050, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1631320447) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 163132040 + ... + 163132049.

It is an arithmetic number, because the mean of its divisors is an integer number (489396135).

Almost surely, 2^1631320445 is an apocalyptic number.

It is an amenable number.

1631320445 is a deficient number, since it is larger than the sum of its proper divisors (326264095).

1631320445 is an equidigital number, since it uses as much as digits as its factorization.

1631320445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 326264094.

The product of its (nonzero) digits is 8640, while the sum is 29.

The square root of 1631320445 is about 40389.6081313003. The cubic root of 1631320445 is about 1177.1896264413.

The spelling of 1631320445 in words is "one billion, six hundred thirty-one million, three hundred twenty thousand, four hundred forty-five".