21510861948 has 18 divisors (see below), whose sum is σ = 54374678904. Its totient is φ = 7170287304.

The previous prime is 21510861887. The next prime is 21510861959. The reversal of 21510861948 is 84916801512.

It is a happy number.

21510861948 is a `hidden beast` number, since 2 + 1 + 510 + 86 + 19 + 48 = 666.

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 298761936 + ... + 298762007.

Almost surely, 2^21510861948 is an apocalyptic number.

It is an amenable number.

21510861948 is an abundant number, since it is smaller than the sum of its proper divisors (32863816956).

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

21510861948 is a wasteful number, since it uses less digits than its factorization.

21510861948 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 597523953 (or 597523948 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 45.

The spelling of 21510861948 in words is "twenty-one billion, five hundred ten million, eight hundred sixty-one thousand, nine hundred forty-eight".