1020021749 has 2 divisors, whose sum is σ = 1020021750. Its totient is φ = 1020021748.

The previous prime is 1020021721. The next prime is 1020021757. The reversal of 1020021749 is 9471200201.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 739459249 + 280562500 = 27193^2 + 16750^2 .

It is a cyclic number.

It is not a de Polignac number, because 1020021749 - 2¹² = 1020017653 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1020021719) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510010874 + 510010875.

It is an arithmetic number, because the mean of its divisors is an integer number (510010875).

Almost surely, 2^1020021749 is an apocalyptic number.

It is an amenable number.

1020021749 is a deficient number, since it is larger than the sum of its proper divisors (1).

1020021749 is an equidigital number, since it uses as much as digits as its factorization.

1020021749 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1008, while the sum is 26.

The square root of 1020021749 is about 31937.7793373303. The cubic root of 1020021749 is about 1006.6298640966.

The spelling of 1020021749 in words is "one billion, twenty million, twenty-one thousand, seven hundred forty-nine".