21409950 has 24 divisors (see below), whose sum is σ = 53097048. Its totient is φ = 5709280.

The previous prime is 21409931. The next prime is 21409991. The reversal of 21409950 is 5990412.

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 a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 71217 + ... + 71516.

It is an arithmetic number, because the mean of its divisors is an integer number (2212377).

Almost surely, 2^21409950 is an apocalyptic number.

21409950 is an abundant number, since it is smaller than the sum of its proper divisors (31687098).

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

21409950 is a wasteful number, since it uses less digits than its factorization.

21409950 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142748 (or 142743 counting only the distinct ones).

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

The square root of 21409950 is about 4627.0887175415. The cubic root of 21409950 is about 277.6761319950.

It can be divided in two parts, 2140 and 9950, that added together give a triangular number (12090 = T₁₅₅).

The spelling of 21409950 in words is "twenty-one million, four hundred nine thousand, nine hundred fifty".