4921781 has 2 divisors, whose sum is σ = 4921782. Its totient is φ = 4921780.

The previous prime is 4921771. The next prime is 4921783. The reversal of 4921781 is 1871294.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2775556 + 2146225 = 1666^2 + 1465^2 .

It is a cyclic number.

It is not a de Polignac number, because 4921781 - 2⁶ = 4921717 is a prime.

It is a super-2 number, since 2×4921781² = 48447856423922, which contains 22 as substring.

Together with 4921783, it forms a pair of twin primes.

It is a Chen prime.

It is a zygodrome in base 5.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4921783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2460890 + 2460891.

It is an arithmetic number, because the mean of its divisors is an integer number (2460891).

Almost surely, 2^4921781 is an apocalyptic number.

It is an amenable number.

4921781 is a deficient number, since it is larger than the sum of its proper divisors (1).

4921781 is an equidigital number, since it uses as much as digits as its factorization.

4921781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4032, while the sum is 32.

The square root of 4921781 is about 2218.5087333612. The cubic root of 4921781 is about 170.1012199973.

The spelling of 4921781 in words is "four million, nine hundred twenty-one thousand, seven hundred eighty-one".