21192240 has 40 divisors (see below), whose sum is σ = 65696688. Its totient is φ = 5651200.

The previous prime is 21192233. The next prime is 21192247. The reversal of 21192240 is 4229112.

It is an interprime number because it is at equal distance from previous prime (21192233) and next prime (21192247).

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×21192240² = 898222072435200, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21192247) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43911 + ... + 44390.

Almost surely, 2^21192240 is an apocalyptic number.

21192240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21192240 is an abundant number, since it is smaller than the sum of its proper divisors (44504448).

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

21192240 is a wasteful number, since it uses less digits than its factorization.

21192240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88317 (or 88311 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 21192240 is about 4603.5030140101. The cubic root of 21192240 is about 276.7317277354.

The spelling of 21192240 in words is "twenty-one million, one hundred ninety-two thousand, two hundred forty".