919120021 has 2 divisors, whose sum is σ = 919120022. Its totient is φ = 919120020.

The previous prime is 919120019. The next prime is 919120061. The reversal of 919120021 is 120021919.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 777628996 + 141491025 = 27886^2 + 11895^2 .

It is a cyclic number.

It is not a de Polignac number, because 919120021 - 2¹ = 919120019 is a prime.

It is a super-2 number, since 2×919120021² = 1689563226006080882, which contains 22 as substring.

Together with 919120019, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (919120061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 459560010 + 459560011.

It is an arithmetic number, because the mean of its divisors is an integer number (459560011).

Almost surely, 2^919120021 is an apocalyptic number.

It is an amenable number.

919120021 is a deficient number, since it is larger than the sum of its proper divisors (1).

919120021 is an equidigital number, since it uses as much as digits as its factorization.

919120021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324, while the sum is 25.

The square root of 919120021 is about 30316.9922815572. The cubic root of 919120021 is about 972.2786339133.

The spelling of 919120021 in words is "nine hundred nineteen million, one hundred twenty thousand, twenty-one".