1640427 has 12 divisors (see below), whose sum is σ = 2264040. Its totient is φ = 1056480.

The previous prime is 1640423. The next prime is 1640447. The reversal of 1640427 is 7240461.

It is not a de Polignac number, because 1640427 - 2² = 1640423 is a prime.

1640427 is a lucky number.

It is a plaindrome in base 13.

It is a junction number, because it is equal to n+sod(n) for n = 1640397 and 1640406.

It is not an unprimeable number, because it can be changed into a prime (1640423) 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, 2599 + ... + 3167.

It is an arithmetic number, because the mean of its divisors is an integer number (188670).

2^1640427 is an apocalyptic number.

1640427 is a deficient number, since it is larger than the sum of its proper divisors (623613).

1640427 is an equidigital number, since it uses as much as digits as its factorization.

1640427 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 634 (or 603 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 1640427 is about 1280.7915521270. The cubic root of 1640427 is about 117.9376046648.

Adding to 1640427 its reverse (7240461), we get a palindrome (8880888).

The spelling of 1640427 in words is "one million, six hundred forty thousand, four hundred twenty-seven".