21426977 has 8 divisors (see below), whose sum is σ = 25173120. Its totient is φ = 17980560.

The previous prime is 21426973. The next prime is 21426991. The reversal of 21426977 is 77962412.

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

It is not a de Polignac number, because 21426977 - 2² = 21426973 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21426977.

It is not an unprimeable number, because it can be changed into a prime (21426973) 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, 74777 + ... + 75062.

It is an arithmetic number, because the mean of its divisors is an integer number (3146640).

Almost surely, 2^21426977 is an apocalyptic number.

It is an amenable number.

21426977 is a deficient number, since it is larger than the sum of its proper divisors (3746143).

21426977 is a wasteful number, since it uses less digits than its factorization.

21426977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 149863.

The product of its digits is 42336, while the sum is 38.

The square root of 21426977 is about 4628.9282776902. The cubic root of 21426977 is about 277.7497229918.

It can be divided in two parts, 2142 and 6977, that added together give a palindrome (9119).

The spelling of 21426977 in words is "twenty-one million, four hundred twenty-six thousand, nine hundred seventy-seven".