21053435240 has 16 divisors (see below), whose sum is σ = 47370229380. Its totient is φ = 8421374080.

The previous prime is 21053435191. The next prime is 21053435281. The reversal of 21053435240 is 4253435012.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 19802681284 + 1250753956 = 140722^2 + 35366^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 263167901 + ... + 263167980.

Almost surely, 2^21053435240 is an apocalyptic number.

21053435240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21053435240 is an abundant number, since it is smaller than the sum of its proper divisors (26316794140).

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

21053435240 is a wasteful number, since it uses less digits than its factorization.

21053435240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 526335892 (or 526335888 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 29.

The spelling of 21053435240 in words is "twenty-one billion, fifty-three million, four hundred thirty-five thousand, two hundred forty".