1644554461 has 4 divisors (see below), whose sum is σ = 1794059424. Its totient is φ = 1495049500.

The previous prime is 1644554419. The next prime is 1644554489.

It is a happy number.

1644554461 is nontrivially palindromic in base 10.

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.

It is a cyclic number.

It is not a de Polignac number, because 1644554461 - 2¹⁹ = 1644030173 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1644552461) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 74752465 + ... + 74752486.

It is an arithmetic number, because the mean of its divisors is an integer number (448514856).

Almost surely, 2^1644554461 is an apocalyptic number.

1644554461 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1644554461 is a deficient number, since it is larger than the sum of its proper divisors (149504963).

1644554461 is a wasteful number, since it uses less digits than its factorization.

1644554461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149504962.

The product of its digits is 230400, while the sum is 40.

The square root of 1644554461 is about 40553.1066750748. The cubic root of 1644554461 is about 1180.3643567452.

The spelling of 1644554461 in words is "one billion, six hundred forty-four million, five hundred fifty-four thousand, four hundred sixty-one".