21100340 has 12 divisors (see below), whose sum is σ = 44310756. Its totient is φ = 8440128.

The previous prime is 21100319. The next prime is 21100351. The reversal of 21100340 is 4300112.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 12124324 + 8976016 = 3482^2 + 2996^2 .

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 527489 + ... + 527528.

It is an arithmetic number, because the mean of its divisors is an integer number (3692563).

Almost surely, 2^21100340 is an apocalyptic number.

21100340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21100340 is an abundant number, since it is smaller than the sum of its proper divisors (23210416).

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

21100340 is a wasteful number, since it uses less digits than its factorization.

21100340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1055026 (or 1055024 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 21100340 is about 4593.5106400225. The cubic root of 21100340 is about 276.3311330526.

Adding to 21100340 its reverse (4300112), we get a palindrome (25400452).

The spelling of 21100340 in words is "twenty-one million, one hundred thousand, three hundred forty".