21351948 has 12 divisors (see below), whose sum is σ = 49821240. Its totient is φ = 7117312.

The previous prime is 21351947. The next prime is 21351971. The reversal of 21351948 is 84915312.

It is a tau number, because it is divible by the number of its divisors (12).

It is a super-3 number, since 3×21351948³ (a number of 23 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (21351943) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 889653 + ... + 889676.

It is an arithmetic number, because the mean of its divisors is an integer number (4151770).

Almost surely, 2^21351948 is an apocalyptic number.

It is an amenable number.

21351948 is an abundant number, since it is smaller than the sum of its proper divisors (28469292).

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

21351948 is a wasteful number, since it uses less digits than its factorization.

21351948 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1779336 (or 1779334 counting only the distinct ones).

The product of its digits is 8640, while the sum is 33.

The square root of 21351948 is about 4620.8168109112. The cubic root of 21351948 is about 277.4251530956.

The spelling of 21351948 in words is "twenty-one million, three hundred fifty-one thousand, nine hundred forty-eight".