1021990445 has 16 divisors (see below), whose sum is σ = 1484034048. Its totient is φ = 659569920.

The previous prime is 1021990433. The next prime is 1021990447. The reversal of 1021990445 is 5440991201.

It is not a de Polignac number, because 1021990445 - 2⁴ = 1021990429 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1021990447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 858221 + ... + 859410.

It is an arithmetic number, because the mean of its divisors is an integer number (92752128).

Almost surely, 2^1021990445 is an apocalyptic number.

It is an amenable number.

1021990445 is a deficient number, since it is larger than the sum of its proper divisors (462043603).

1021990445 is a wasteful number, since it uses less digits than its factorization.

1021990445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1717660.

The product of its (nonzero) digits is 12960, while the sum is 35.

The square root of 1021990445 is about 31968.5852830556. The cubic root of 1021990445 is about 1007.2770642158.

The spelling of 1021990445 in words is "one billion, twenty-one million, nine hundred ninety thousand, four hundred forty-five".