21507950 has 24 divisors (see below), whose sum is σ = 40410360. Its totient is φ = 8516000.

The previous prime is 21507947. The next prime is 21507953. The reversal of 21507950 is 5970512.

It is an interprime number because it is at equal distance from previous prime (21507947) and next prime (21507953).

It is a hoax number, since the sum of its digits (29) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21507953) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2921 + ... + 7179.

It is an arithmetic number, because the mean of its divisors is an integer number (1683765).

Almost surely, 2^21507950 is an apocalyptic number.

21507950 is a deficient number, since it is larger than the sum of its proper divisors (18902410).

21507950 is a wasteful number, since it uses less digits than its factorization.

21507950 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4372 (or 4367 counting only the distinct ones).

The product of its (nonzero) digits is 3150, while the sum is 29.

The square root of 21507950 is about 4637.6664390618. Note that the first 3 decimals coincide. The cubic root of 21507950 is about 278.0991572167.

The spelling of 21507950 in words is "twenty-one million, five hundred seven thousand, nine hundred fifty".