1021399985 has 16 divisors (see below), whose sum is σ = 1313542656. Its totient is φ = 760465728.

The previous prime is 1021399979. The next prime is 1021399991. The reversal of 1021399985 is 5899931201.

It is an interprime number because it is at equal distance from previous prime (1021399979) and next prime (1021399991).

It is a cyclic number.

It is not a de Polignac number, because 1021399985 - 2⁴ = 1021399969 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 115769 + ... + 124278.

It is an arithmetic number, because the mean of its divisors is an integer number (82096416).

Almost surely, 2^1021399985 is an apocalyptic number.

It is an amenable number.

1021399985 is a deficient number, since it is larger than the sum of its proper divisors (292142671).

1021399985 is a wasteful number, since it uses less digits than its factorization.

1021399985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240112.

The product of its (nonzero) digits is 174960, while the sum is 47.

The square root of 1021399985 is about 31959.3489451835. The cubic root of 1021399985 is about 1007.0830404210.

The spelling of 1021399985 in words is "one billion, twenty-one million, three hundred ninety-nine thousand, nine hundred eighty-five".