21212122222090 has 16 divisors (see below), whose sum is σ = 38181981580488. Its totient is φ = 8484812982016.

The previous prime is 21212122222073. The next prime is 21212122222103. The reversal of 21212122222090 is 9022222121212.

It can be written as a sum of positive squares in 4 ways, for example, as 11358807500089 + 9853314722001 = 3370283^2 + 3138999^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1938187 + ... + 6795646.

Almost surely, 2^{21212122222090} is an apocalyptic number.

21212122222090 is a deficient number, since it is larger than the sum of its proper divisors (16969859358398).

21212122222090 is a wasteful number, since it uses less digits than its factorization.

21212122222090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8976713.

The product of its (nonzero) digits is 2304, while the sum is 28.

The spelling of 21212122222090 in words is "twenty-one trillion, two hundred twelve billion, one hundred twenty-two million, two hundred twenty-two thousand, ninety".