1156389021 has 16 divisors (see below), whose sum is σ = 1713813120. Its totient is φ = 770636160.

The previous prime is 1156388941. The next prime is 1156389041. The reversal of 1156389021 is 1209836511.

1156389021 is a `hidden beast` number, since 1 + 1 + 563 + 8 + 90 + 2 + 1 = 666.

It is not a de Polignac number, because 1156389021 - 2²² = 1152194717 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1156389041) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 84376 + ... + 97118.

It is an arithmetic number, because the mean of its divisors is an integer number (107113320).

Almost surely, 2^1156389021 is an apocalyptic number.

It is an amenable number.

1156389021 is a deficient number, since it is larger than the sum of its proper divisors (557424099).

1156389021 is a wasteful number, since it uses less digits than its factorization.

1156389021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16113 (or 16107 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 1156389021 is about 34005.7204158359. The cubic root of 1156389021 is about 1049.6261771308.

The spelling of 1156389021 in words is "one billion, one hundred fifty-six million, three hundred eighty-nine thousand, twenty-one".