21538941270 has 384 divisors, whose sum is σ = 67697482752. Its totient is φ = 4335206400.

The previous prime is 21538941247. The next prime is 21538941337. The reversal of 21538941270 is 7214983512.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 83808982 + ... + 83809238.

It is an arithmetic number, because the mean of its divisors is an integer number (176295528).

Almost surely, 2^21538941270 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21538941270, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33848741376).

21538941270 is an abundant number, since it is smaller than the sum of its proper divisors (46158541482).

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

21538941270 is a wasteful number, since it uses less digits than its factorization.

21538941270 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 436 (or 429 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 42.

The spelling of 21538941270 in words is "twenty-one billion, five hundred thirty-eight million, nine hundred forty-one thousand, two hundred seventy".