1021815649 has 8 divisors (see below), whose sum is σ = 1075932000. Its totient is φ = 967732992.

The previous prime is 1021815629. The next prime is 1021815661. The reversal of 1021815649 is 9465181201.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1021815649 - 2¹⁹ = 1021291361 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1021815629) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75222 + ... + 87760.

It is an arithmetic number, because the mean of its divisors is an integer number (134491500).

Almost surely, 2^1021815649 is an apocalyptic number.

1021815649 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

1021815649 is a deficient number, since it is larger than the sum of its proper divisors (54116351).

1021815649 is a wasteful number, since it uses less digits than its factorization.

1021815649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16847.

The product of its (nonzero) digits is 17280, while the sum is 37.

The square root of 1021815649 is about 31965.8512947802. The cubic root of 1021815649 is about 1007.2196344419.

The spelling of 1021815649 in words is "one billion, twenty-one million, eight hundred fifteen thousand, six hundred forty-nine".