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30991090 = 25131912547
BaseRepresentation
bin111011000111…
…0001011110010
32011022111210011
41312032023302
530413203330
63024125134
7524264014
oct166161362
964274704
1030991090
1116548079
12a4667aa
136561130
14418a1b4
152ac282a
hex1d8e2f2

30991090 has 32 divisors (see below), whose sum is σ = 63241920. Its totient is φ = 10839744.

The previous prime is 30991067. The next prime is 30991091. The reversal of 30991090 is 9019903.

Subtracting from 30991090 its product of nonzero digits (2187), we obtain a palindrome (30988903).

It is not an unprimeable number, because it can be changed into a prime (30991091) 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, 3804 + ... + 8743.

It is an arithmetic number, because the mean of its divisors is an integer number (1976310).

Almost surely, 230991090 is an apocalyptic number.

30991090 is an abundant number, since it is smaller than the sum of its proper divisors (32250830).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

30991090 is a wasteful number, since it uses less digits than its factorization.

30991090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12586.

The product of its (nonzero) digits is 2187, while the sum is 31.

The square root of 30991090 is about 5566.9641637072. The cubic root of 30991090 is about 314.1079659019.

The spelling of 30991090 in words is "thirty million, nine hundred ninety-one thousand, ninety".

Divisors: 1 2 5 10 13 19 26 38 65 95 130 190 247 494 1235 2470 12547 25094 62735 125470 163111 238393 326222 476786 815555 1191965 1631110 2383930 3099109 6198218 15495545 30991090