1642691 has 4 divisors (see below), whose sum is σ = 1653312. Its totient is φ = 1632072.

The previous prime is 1642679. The next prime is 1642699. The reversal of 1642691 is 1962461.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1642691 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1642699) 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, 5075 + ... + 5388.

It is an arithmetic number, because the mean of its divisors is an integer number (413328).

2^1642691 is an apocalyptic number.

1642691 is a deficient number, since it is larger than the sum of its proper divisors (10621).

1642691 is a wasteful number, since it uses less digits than its factorization.

1642691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10620.

The product of its digits is 2592, while the sum is 29.

The square root of 1642691 is about 1281.6750758285. The cubic root of 1642691 is about 117.9918360722.

The spelling of 1642691 in words is "one million, six hundred forty-two thousand, six hundred ninety-one".