21111690 has 32 divisors (see below), whose sum is σ = 51243840. Its totient is φ = 5565824.

The previous prime is 21111683. The next prime is 21111697. The reversal of 21111690 is 9611112.

It is an interprime number because it is at equal distance from previous prime (21111683) and next prime (21111697).

It is a super-2 number, since 2×21111690² = 891406909312200, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21111697) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1284 + ... + 6623.

It is an arithmetic number, because the mean of its divisors is an integer number (1601370).

Almost surely, 2^21111690 is an apocalyptic number.

21111690 is an abundant number, since it is smaller than the sum of its proper divisors (30132150).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21111690 is a wasteful number, since it uses less digits than its factorization.

21111690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8006.

The product of its (nonzero) digits is 108, while the sum is 21.

The square root of 21111690 is about 4594.7459124526. The cubic root of 21111690 is about 276.3806708985.

The spelling of 21111690 in words is "twenty-one million, one hundred eleven thousand, six hundred ninety".