1640000391 has 8 divisors (see below), whose sum is σ = 2187433584. Its totient is φ = 1092950400.

The previous prime is 1640000389. The next prime is 1640000413. The reversal of 1640000391 is 1930000461.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1640000391 - 2¹ = 1640000389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640000891) 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, 85660 + ... + 103041.

It is an arithmetic number, because the mean of its divisors is an integer number (273429198).

Almost surely, 2^1640000391 is an apocalyptic number.

1640000391 is the 25613-rd centered pentagonal number.

1640000391 is a deficient number, since it is larger than the sum of its proper divisors (547433193).

1640000391 is a wasteful number, since it uses less digits than its factorization.

1640000391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191601.

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 1640000391 is about 40496.9182901613. The cubic root of 1640000391 is about 1179.2738017128.

The spelling of 1640000391 in words is "one billion, six hundred forty million, three hundred ninety-one", and thus it is an aban number.