1621144461 has 4 divisors (see below), whose sum is σ = 2161525952. Its totient is φ = 1080762972.

The previous prime is 1621144453. The next prime is 1621144471. The reversal of 1621144461 is 1644411261.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1644411261 = 3 ⋅548137087.

It is not a de Polignac number, because 1621144461 - 2³ = 1621144453 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 (1621144451) 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 3 ways as a sum of consecutive naturals, for example, 270190741 + ... + 270190746.

It is an arithmetic number, because the mean of its divisors is an integer number (540381488).

Almost surely, 2^1621144461 is an apocalyptic number.

It is an amenable number.

1621144461 is a deficient number, since it is larger than the sum of its proper divisors (540381491).

1621144461 is an equidigital number, since it uses as much as digits as its factorization.

1621144461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 540381490.

The product of its digits is 4608, while the sum is 30.

The square root of 1621144461 is about 40263.4382660001. The cubic root of 1621144461 is about 1174.7367959726.

The spelling of 1621144461 in words is "one billion, six hundred twenty-one million, one hundred forty-four thousand, four hundred sixty-one".