1620971 has 16 divisors (see below), whose sum is σ = 1900800. Its totient is φ = 1367520.

The previous prime is 1620961. The next prime is 1620973. The reversal of 1620971 is 1790261.

It is a de Polignac number, because none of the positive numbers 2^k-1620971 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1620971.

It is not an unprimeable number, because it can be changed into a prime (1620973) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10805 + ... + 10953.

It is an arithmetic number, because the mean of its divisors is an integer number (118800).

2^1620971 is an apocalyptic number.

1620971 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1620971 is a deficient number, since it is larger than the sum of its proper divisors (279829).

1620971 is a wasteful number, since it uses less digits than its factorization.

1620971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 226.

The product of its (nonzero) digits is 756, while the sum is 26.

The square root of 1620971 is about 1273.1735938198. The cubic root of 1620971 is about 117.4694895884.

The spelling of 1620971 in words is "one million, six hundred twenty thousand, nine hundred seventy-one".