1651721923 has 2 divisors, whose sum is σ = 1651721924. Its totient is φ = 1651721922.

The previous prime is 1651721909. The next prime is 1651721959. The reversal of 1651721923 is 3291271561.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1651721923 - 2²¹ = 1649624771 is a prime.

It is not a weakly prime, because it can be changed into another prime (1651721023) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 825860961 + 825860962.

It is an arithmetic number, because the mean of its divisors is an integer number (825860962).

Almost surely, 2^1651721923 is an apocalyptic number.

1651721923 is a deficient number, since it is larger than the sum of its proper divisors (1).

1651721923 is an equidigital number, since it uses as much as digits as its factorization.

1651721923 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22680, while the sum is 37.

The square root of 1651721923 is about 40641.3819031784. The cubic root of 1651721923 is about 1182.0766656258.

The spelling of 1651721923 in words is "one billion, six hundred fifty-one million, seven hundred twenty-one thousand, nine hundred twenty-three".