1621667 has 2 divisors, whose sum is σ = 1621668. Its totient is φ = 1621666.

The previous prime is 1621657. The next prime is 1621679. The reversal of 1621667 is 7661261.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1621667 is a prime.

It is not a weakly prime, because it can be changed into another prime (1621637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 810833 + 810834.

It is an arithmetic number, because the mean of its divisors is an integer number (810834).

2^1621667 is an apocalyptic number.

1621667 is a deficient number, since it is larger than the sum of its proper divisors (1).

1621667 is an equidigital number, since it uses as much as digits as its factorization.

1621667 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 29.

The square root of 1621667 is about 1273.4468972046. The cubic root of 1621667 is about 117.4862998966.

The spelling of 1621667 in words is "one million, six hundred twenty-one thousand, six hundred sixty-seven".