1997667 has 24 divisors (see below), whose sum is σ = 3390816. Its totient is φ = 1109376.

The previous prime is 1997663. The next prime is 1997683. The reversal of 1997667 is 7667991.

It is not a de Polignac number, because 1997667 - 2² = 1997663 is a prime.

It is an Ulam number.

1997667 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1997663) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1903 + ... + 2759.

It is an arithmetic number, because the mean of its divisors is an integer number (141284).

2^1997667 is an apocalyptic number.

1997667 is a deficient number, since it is larger than the sum of its proper divisors (1393149).

1997667 is a wasteful number, since it uses less digits than its factorization.

1997667 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 907 (or 904 counting only the distinct ones).

The product of its digits is 142884, while the sum is 45.

The square root of 1997667 is about 1413.3884816285. The cubic root of 1997667 is about 125.9430959981.

The spelling of 1997667 in words is "one million, nine hundred ninety-seven thousand, six hundred sixty-seven".