1621972 has 24 divisors (see below), whose sum is σ = 3128832. Its totient is φ = 729600.

The previous prime is 1621933. The next prime is 1621979. The reversal of 1621972 is 2791261.

It is a happy number.

It is a hoax number, since the sum of its digits (28) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 1621972.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8308 + ... + 8500.

It is an arithmetic number, because the mean of its divisors is an integer number (130368).

2^1621972 is an apocalyptic number.

It is an amenable number.

1621972 is a deficient number, since it is larger than the sum of its proper divisors (1506860).

1621972 is a wasteful number, since it uses less digits than its factorization.

1621972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 399 (or 397 counting only the distinct ones).

The product of its digits is 1512, while the sum is 28.

The square root of 1621972 is about 1273.5666452919. The cubic root of 1621972 is about 117.4936649670.

The spelling of 1621972 in words is "one million, six hundred twenty-one thousand, nine hundred seventy-two".