1621791 has 12 divisors (see below), whose sum is σ = 2373280. Its totient is φ = 1067040.

The previous prime is 1621771. The next prime is 1621793. The reversal of 1621791 is 1971261.

It is not a de Polignac number, because 1621791 - 2⁶ = 1621727 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1621793) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 430 + ... + 1851.

2^1621791 is an apocalyptic number.

1621791 is a deficient number, since it is larger than the sum of its proper divisors (751489).

1621791 is a wasteful number, since it uses less digits than its factorization.

1621791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2366 (or 2363 counting only the distinct ones).

The product of its digits is 756, while the sum is 27.

The square root of 1621791 is about 1273.4955830312. The cubic root of 1621791 is about 117.4892943317.

It can be divided in two parts, 162 and 1791, that added together give a triangular number (1953 = T₆₂).

The spelling of 1621791 in words is "one million, six hundred twenty-one thousand, seven hundred ninety-one".