21892345 has 16 divisors (see below), whose sum is σ = 28572048. Its totient is φ = 16035840.

The previous prime is 21892333. The next prime is 21892357. The reversal of 21892345 is 54329812.

21892345 = T₁₄₂ + T₁₄₃ + ... + T₅₁₁.

21892345 = 3308² + 3309².

It is an interprime number because it is at equal distance from previous prime (21892333) and next prime (21892357).

It can be written as a sum of positive squares in 8 ways, for example, as 4227136 + 17665209 = 2056^2 + 4203^2 .

It is not a de Polignac number, because 21892345 - 2¹³ = 21884153 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21892345.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 336 + ... + 6625.

It is an arithmetic number, because the mean of its divisors is an integer number (1785753).

Almost surely, 2^21892345 is an apocalyptic number.

21892345 is the 3309-th centered square number.

It is an amenable number.

21892345 is a deficient number, since it is larger than the sum of its proper divisors (6679703).

21892345 is a wasteful number, since it uses less digits than its factorization.

21892345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7020.

The product of its digits is 17280, while the sum is 34.

The square root of 21892345 is about 4678.9256245425. The cubic root of 21892345 is about 279.7461346955.

The spelling of 21892345 in words is "twenty-one million, eight hundred ninety-two thousand, three hundred forty-five".