21370455 has 12 divisors (see below), whose sum is σ = 37042200. Its totient is φ = 11397552.

The previous prime is 21370451. The next prime is 21370457. The reversal of 21370455 is 55407312.

It is a happy number.

It is not a de Polignac number, because 21370455 - 2² = 21370451 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21370451) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 237405 + ... + 237494.

It is an arithmetic number, because the mean of its divisors is an integer number (3086850).

Almost surely, 2^21370455 is an apocalyptic number.

21370455 is a deficient number, since it is larger than the sum of its proper divisors (15671745).

21370455 is a wasteful number, since it uses less digits than its factorization.

21370455 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 474910 (or 474907 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 27.

The square root of 21370455 is about 4622.8189451892. The cubic root of 21370455 is about 277.5052835614.

Adding to 21370455 its reverse (55407312), we get a palindrome (76777767).

The spelling of 21370455 in words is "twenty-one million, three hundred seventy thousand, four hundred fifty-five".