21111344890 has 16 divisors (see below), whose sum is σ = 39310780680. Its totient is φ = 8153346880.

The previous prime is 21111344873. The next prime is 21111344909. The reversal of 21111344890 is 9844311112.

It can be written as a sum of positive squares in 4 ways, for example, as 13384407481 + 7726937409 = 115691^2 + 87903^2 .

It is a super-2 number, since 2×21111344890² (a number of 21 digits) contains 22 as substring.

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, 36398581 + ... + 36399160.

Almost surely, 2^21111344890 is an apocalyptic number.

21111344890 is a deficient number, since it is larger than the sum of its proper divisors (18199435790).

21111344890 is a wasteful number, since it uses less digits than its factorization.

21111344890 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72797777.

The product of its (nonzero) digits is 6912, while the sum is 34.

The spelling of 21111344890 in words is "twenty-one billion, one hundred eleven million, three hundred forty-four thousand, eight hundred ninety".