612817921 has 4 divisors (see below), whose sum is σ = 648866052. Its totient is φ = 576769792.

The previous prime is 612817883. The next prime is 612817927. The reversal of 612817921 is 129718216.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 331786225 + 281031696 = 18215^2 + 16764^2 .

It is a cyclic number.

It is not a de Polignac number, because 612817921 - 2²³ = 604429313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (612817927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18024040 + ... + 18024073.

It is an arithmetic number, because the mean of its divisors is an integer number (162216513).

Almost surely, 2^612817921 is an apocalyptic number.

It is an amenable number.

612817921 is a deficient number, since it is larger than the sum of its proper divisors (36048131).

612817921 is a wasteful number, since it uses less digits than its factorization.

612817921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36048130.

The product of its digits is 12096, while the sum is 37.

The square root of 612817921 is about 24755.1594824190. The cubic root of 612817921 is about 849.3965363739.

The spelling of 612817921 in words is "six hundred twelve million, eight hundred seventeen thousand, nine hundred twenty-one".