21501992 has 16 divisors (see below), whose sum is σ = 41706900. Its totient is φ = 10380160.

The previous prime is 21501967. The next prime is 21502001. The reversal of 21501992 is 29910512.

It can be written as a sum of positive squares in 2 ways, for example, as 21031396 + 470596 = 4586^2 + 686^2 .

It is a Harshad number since it is a multiple of its sum of digits (29).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46109 + ... + 46572.

Almost surely, 2^21501992 is an apocalyptic number.

It is an amenable number.

21501992 is a deficient number, since it is larger than the sum of its proper divisors (20204908).

21501992 is a wasteful number, since it uses less digits than its factorization.

21501992 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92716 (or 92712 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 29.

The square root of 21501992 is about 4637.0240456569. The cubic root of 21501992 is about 278.0734757393.

The spelling of 21501992 in words is "twenty-one million, five hundred one thousand, nine hundred ninety-two".