19930921 has 2 divisors, whose sum is σ = 19930922. Its totient is φ = 19930920.

The previous prime is 19930891. The next prime is 19930991. The reversal of 19930921 is 12903991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11978521 + 7952400 = 3461^2 + 2820^2 .

It is a cyclic number.

It is not a de Polignac number, because 19930921 - 2¹³ = 19922729 is a prime.

It is a super-2 number, since 2×19930921² = 794483223816482, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (19930991) 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 as a sum of consecutive naturals, namely, 9965460 + 9965461.

It is an arithmetic number, because the mean of its divisors is an integer number (9965461).

Almost surely, 2^19930921 is an apocalyptic number.

It is an amenable number.

19930921 is a deficient number, since it is larger than the sum of its proper divisors (1).

19930921 is an equidigital number, since it uses as much as digits as its factorization.

19930921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4374, while the sum is 34.

The square root of 19930921 is about 4464.4060075222. The cubic root of 19930921 is about 271.1288857390.

The spelling of 19930921 in words is "nineteen million, nine hundred thirty thousand, nine hundred twenty-one".