21392460 has 72 divisors (see below), whose sum is σ = 68717376. Its totient is φ = 5368320.

The previous prime is 21392453. The next prime is 21392467. The reversal of 21392460 is 6429312.

It is an interprime number because it is at equal distance from previous prime (21392453) and next prime (21392467).

It is not an unprimeable number, because it can be changed into a prime (21392467) 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 23 ways as a sum of consecutive naturals, for example, 436 + ... + 6555.

It is an arithmetic number, because the mean of its divisors is an integer number (954408).

Almost surely, 2^21392460 is an apocalyptic number.

21392460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21392460, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34358688).

21392460 is an abundant number, since it is smaller than the sum of its proper divisors (47324916).

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

21392460 is a wasteful number, since it uses less digits than its factorization.

21392460 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7023 (or 7018 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 21392460 is about 4625.1983741241. The cubic root of 21392460 is about 277.6004992696.

The spelling of 21392460 in words is "twenty-one million, three hundred ninety-two thousand, four hundred sixty".