21492278640 has 640 divisors, whose sum is σ = 90279936000. Its totient is φ = 4590203904.

The previous prime is 21492278627. The next prime is 21492278767. The reversal of 21492278640 is 4687229412.

21492278640 is a `hidden beast` number, since 21 + 492 + 27 + 86 + 40 = 666.

It is a super-2 number, since 2×21492278640² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

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 127 ways as a sum of consecutive naturals, for example, 22694647 + ... + 22695593.

It is an arithmetic number, because the mean of its divisors is an integer number (141062400).

Almost surely, 2^21492278640 is an apocalyptic number.

21492278640 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 21492278640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45139968000).

21492278640 is an abundant number, since it is smaller than the sum of its proper divisors (68787657360).

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

21492278640 is a wasteful number, since it uses less digits than its factorization.

21492278640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1074 (or 1062 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 45.

The spelling of 21492278640 in words is "twenty-one billion, four hundred ninety-two million, two hundred seventy-eight thousand, six hundred forty".