21099450 has 24 divisors (see below), whose sum is σ = 52327008. Its totient is φ = 5626480.

The previous prime is 21099427. The next prime is 21099451. The reversal of 21099450 is 5499012.

It is a happy number.

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (21099451) 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, 70182 + ... + 70481.

It is an arithmetic number, because the mean of its divisors is an integer number (2180292).

Almost surely, 2^21099450 is an apocalyptic number.

21099450 is an abundant number, since it is smaller than the sum of its proper divisors (31227558).

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

21099450 is a wasteful number, since it uses less digits than its factorization.

21099450 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140678 (or 140673 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 30.

The square root of 21099450 is about 4593.4137632049. The cubic root of 21099450 is about 276.3272478361.

The spelling of 21099450 in words is "twenty-one million, ninety-nine thousand, four hundred fifty".