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30281921 = 531015657
BaseRepresentation
bin111001110000…
…1000011000001
32002222110222122
41303201003001
530223010141
63001014025
7515251325
oct163410301
962873878
1030281921
111610328a
12a184315
1363733c7
144043985
1529d264b
hex1ce10c1

30281921 has 8 divisors (see below), whose sum is σ = 31164264. Its totient is φ = 29411200.

The previous prime is 30281899. The next prime is 30281941. The reversal of 30281921 is 12918203.

It can be written as a sum of positive squares in 4 ways, for example, as 8761600 + 21520321 = 2960^2 + 4639^2 .

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

It is not a de Polignac number, because 30281921 - 210 = 30280897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (30281941) 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, 2525 + ... + 8181.

It is an arithmetic number, because the mean of its divisors is an integer number (3895533).

Almost surely, 230281921 is an apocalyptic number.

It is an amenable number.

30281921 is a deficient number, since it is larger than the sum of its proper divisors (882343).

30281921 is a wasteful number, since it uses less digits than its factorization.

30281921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5811.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 30281921 is about 5502.9011439422. The cubic root of 30281921 is about 311.6935442836.

The spelling of 30281921 in words is "thirty million, two hundred eighty-one thousand, nine hundred twenty-one".

Divisors: 1 53 101 5353 5657 299821 571357 30281921