21561094 has 16 divisors (see below), whose sum is σ = 33574320. Its totient is φ = 10372320.

The previous prime is 21561091. The next prime is 21561101. The reversal of 21561094 is 49016512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21561091) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 23977 + ... + 24859.

It is an arithmetic number, because the mean of its divisors is an integer number (2098395).

Almost surely, 2^21561094 is an apocalyptic number.

21561094 is a deficient number, since it is larger than the sum of its proper divisors (12013226).

21561094 is a wasteful number, since it uses less digits than its factorization.

21561094 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1335.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 21561094 is about 4643.3925097928. The cubic root of 21561094 is about 278.3280205838.

The spelling of 21561094 in words is "twenty-one million, five hundred sixty-one thousand, ninety-four".