1640401447 has 4 divisors (see below), whose sum is σ = 1667293336. Its totient is φ = 1613509560.

The previous prime is 1640401439. The next prime is 1640401457. The reversal of 1640401447 is 7441040461.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1640401447 - 2³ = 1640401439 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640401457) 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, 13445853 + ... + 13445974.

It is an arithmetic number, because the mean of its divisors is an integer number (416823334).

Almost surely, 2^1640401447 is an apocalyptic number.

1640401447 is a deficient number, since it is larger than the sum of its proper divisors (26891889).

1640401447 is an equidigital number, since it uses as much as digits as its factorization.

1640401447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26891888.

The product of its (nonzero) digits is 10752, while the sum is 31.

The square root of 1640401447 is about 40501.8696728929. The cubic root of 1640401447 is about 1179.3699228862.

The spelling of 1640401447 in words is "one billion, six hundred forty million, four hundred one thousand, four hundred forty-seven".