21961404 has 36 divisors (see below), whose sum is σ = 56871360. Its totient is φ = 7141440.

The previous prime is 21961369. The next prime is 21961417. The reversal of 21961404 is 40416912.

It is a tau number, because it is divible by the number of its divisors (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5964 + ... + 8915.

It is an arithmetic number, because the mean of its divisors is an integer number (1579760).

Almost surely, 2^21961404 is an apocalyptic number.

It is an amenable number.

21961404 is an abundant number, since it is smaller than the sum of its proper divisors (34909956).

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

21961404 is a wasteful number, since it uses less digits than its factorization.

21961404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14930 (or 14925 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 21961404 is about 4686.2996062992. The cubic root of 21961404 is about 280.0399772851.

It can be divided in two parts, 2196 and 1404, that added together give a square (3600 = 60²).

The spelling of 21961404 in words is "twenty-one million, nine hundred sixty-one thousand, four hundred four".