21054957 has 48 divisors (see below), whose sum is σ = 36936000. Its totient is φ = 10536960.

The previous prime is 21054953. The next prime is 21054967. The reversal of 21054957 is 75945012.

It is not a de Polignac number, because 21054957 - 2² = 21054953 is a prime.

It is a super-2 number, since 2×21054957² = 886622428543698, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21054953) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 46669 + ... + 47117.

It is an arithmetic number, because the mean of its divisors is an integer number (769500).

Almost surely, 2^21054957 is an apocalyptic number.

It is an amenable number.

21054957 is a deficient number, since it is larger than the sum of its proper divisors (15881043).

21054957 is a wasteful number, since it uses less digits than its factorization.

21054957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 506 (or 499 counting only the distinct ones).

The product of its (nonzero) digits is 12600, while the sum is 33.

The square root of 21054957 is about 4588.5680772982. The cubic root of 21054957 is about 276.1328781505.

Adding to 21054957 its reverse (75945012), we get a palindrome (96999969).

The spelling of 21054957 in words is "twenty-one million, fifty-four thousand, nine hundred fifty-seven".