21399350 has 24 divisors (see below), whose sum is σ = 45489648. Its totient is φ = 7336800.

The previous prime is 21399319. The next prime is 21399353. The reversal of 21399350 is 5399312.

It is a Smith number, since the sum of its digits (32) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21399353) 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, 30221 + ... + 30920.

It is an arithmetic number, because the mean of its divisors is an integer number (1895402).

Almost surely, 2^21399350 is an apocalyptic number.

21399350 is an abundant number, since it is smaller than the sum of its proper divisors (24090298).

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

21399350 is a wasteful number, since it uses less digits than its factorization.

21399350 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 61160 (or 61155 counting only the distinct ones).

The product of its (nonzero) digits is 7290, while the sum is 32.

The square root of 21399350 is about 4625.9431470782. The cubic root of 21399350 is about 277.6302988990.

It can be divided in two parts, 2139 and 9350, that multiplied together give a triangular number (19999650 = T₆₃₂₄).

The spelling of 21399350 in words is "twenty-one million, three hundred ninety-nine thousand, three hundred fifty".