21295440 has 80 divisors (see below), whose sum is σ = 73358400. Its totient is φ = 5678208.

The previous prime is 21295411. The next prime is 21295459. The reversal of 21295440 is 4459212.

21295440 is a `hidden beast` number, since 212 + 9 + 5 + 440 = 666.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2770 + ... + 7089.

It is an arithmetic number, because the mean of its divisors is an integer number (916980).

Almost surely, 2^21295440 is an apocalyptic number.

21295440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21295440 is an abundant number, since it is smaller than the sum of its proper divisors (52062960).

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

21295440 is a wasteful number, since it uses less digits than its factorization.

21295440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9881 (or 9869 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 21295440 is about 4614.6982566577. The cubic root of 21295440 is about 277.1802013558.

It can be divided in two parts, 2129 and 5440, that added together give a square (7569 = 87²).

The spelling of 21295440 in words is "twenty-one million, two hundred ninety-five thousand, four hundred forty".