21149800 has 48 divisors (see below), whose sum is σ = 56201760. Its totient is φ = 7250880.

The previous prime is 21149797. The next prime is 21149803. The reversal of 21149800 is 894112.

21149800 = T₁₀₄ + T₁₀₅ + ... + T₅₀₃.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21149797) and next prime (21149803).

It is a Harshad number since it is a multiple of its sum of digits (25).

It is not an unprimeable number, because it can be changed into a prime (21149803) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6154 + ... + 8953.

It is an arithmetic number, because the mean of its divisors is an integer number (1170870).

Almost surely, 2^21149800 is an apocalyptic number.

21149800 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21149800 is an abundant number, since it is smaller than the sum of its proper divisors (35051960).

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

21149800 is a wasteful number, since it uses less digits than its factorization.

21149800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15130 (or 15121 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 21149800 is about 4598.8911707063. The cubic root of 21149800 is about 276.5468748022.

The spelling of 21149800 in words is "twenty-one million, one hundred forty-nine thousand, eight hundred".