1621742 has 4 divisors (see below), whose sum is σ = 2432616. Its totient is φ = 810870.

The previous prime is 1621729. The next prime is 1621751. The reversal of 1621742 is 2471261.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 2471261 = 13 ⋅190097.

It is a super-2 number, since 2×1621742² = 5260094229128, which contains 22 as substring.

It is a plaindrome in base 16.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 405434 + ... + 405437.

It is an arithmetic number, because the mean of its divisors is an integer number (608154).

2^1621742 is an apocalyptic number.

1621742 is a deficient number, since it is larger than the sum of its proper divisors (810874).

1621742 is an equidigital number, since it uses as much as digits as its factorization.

1621742 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 810873.

The product of its digits is 672, while the sum is 23.

The square root of 1621742 is about 1273.4763444996. The cubic root of 1621742 is about 117.4881110651.

The spelling of 1621742 in words is "one million, six hundred twenty-one thousand, seven hundred forty-two".