21277172 has 18 divisors (see below), whose sum is σ = 43314642. Its totient is φ = 9118704.

The previous prime is 21277163. The next prime is 21277181. The reversal of 21277172 is 27177212.

It is an interprime number because it is at equal distance from previous prime (21277163) and next prime (21277181).

It can be written as a sum of positive squares in only one way, i.e., 17757796 + 3519376 = 4214^2 + 1876^2 .

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 54083 + ... + 54474.

It is an arithmetic number, because the mean of its divisors is an integer number (2406369).

Almost surely, 2^21277172 is an apocalyptic number.

It is an amenable number.

21277172 is an abundant number, since it is smaller than the sum of its proper divisors (22037470).

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

21277172 is a wasteful number, since it uses less digits than its factorization.

21277172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108575 (or 108566 counting only the distinct ones).

The product of its digits is 2744, while the sum is 29.

The square root of 21277172 is about 4612.7185043096. The cubic root of 21277172 is about 277.1009202749.

The spelling of 21277172 in words is "twenty-one million, two hundred seventy-seven thousand, one hundred seventy-two".