1640690371 has 12 divisors (see below), whose sum is σ = 1689548112. Its totient is φ = 1593210528.

The previous prime is 1640690369. The next prime is 1640690377. The reversal of 1640690371 is 1730960461.

It is not a de Polignac number, because 1640690371 - 2¹ = 1640690369 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1640690371.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640690377) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1016361 + ... + 1017973.

It is an arithmetic number, because the mean of its divisors is an integer number (140795676).

It is the magic constant of a 1486 × 1486 magic square.

Almost surely, 2^1640690371 is an apocalyptic number.

1640690371 is a deficient number, since it is larger than the sum of its proper divisors (48857741).

1640690371 is an equidigital number, since it uses as much as digits as its factorization.

1640690371 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2430 (or 2393 counting only the distinct ones).

The product of its (nonzero) digits is 27216, while the sum is 37.

The square root of 1640690371 is about 40505.4363141542. The cubic root of 1640690371 is about 1179.4391596519.

The spelling of 1640690371 in words is "one billion, six hundred forty million, six hundred ninety thousand, three hundred seventy-one".