21938477 has 8 divisors (see below), whose sum is σ = 24222240. Its totient is φ = 19702960.

The previous prime is 21938473. The next prime is 21938479. The reversal of 21938477 is 77483912.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21938477 - 2² = 21938473 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21938473) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11102 + ... + 12927.

It is an arithmetic number, because the mean of its divisors is an integer number (3027780).

Almost surely, 2^21938477 is an apocalyptic number.

It is an amenable number.

21938477 is a deficient number, since it is larger than the sum of its proper divisors (2283763).

21938477 is a wasteful number, since it uses less digits than its factorization.

21938477 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24123.

The product of its digits is 84672, while the sum is 41.

The square root of 21938477 is about 4683.8527944418. The cubic root of 21938477 is about 279.9424924414.

The spelling of 21938477 in words is "twenty-one million, nine hundred thirty-eight thousand, four hundred seventy-seven".