21572154 has 48 divisors (see below), whose sum is σ = 48926592. Its totient is φ = 6862464.

The previous prime is 21572141. The next prime is 21572179. The reversal of 21572154 is 45127512.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 36082 + ... + 36674.

It is an arithmetic number, because the mean of its divisors is an integer number (1019304).

Almost surely, 2^21572154 is an apocalyptic number.

21572154 is an abundant number, since it is smaller than the sum of its proper divisors (27354438).

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

21572154 is a wasteful number, since it uses less digits than its factorization.

21572154 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 691 (or 688 counting only the distinct ones).

The product of its digits is 2800, while the sum is 27.

The square root of 21572154 is about 4644.5832967017. The cubic root of 21572154 is about 278.3756029205.

Adding to 21572154 its reverse (45127512), we get a palindrome (66699666).

The spelling of 21572154 in words is "twenty-one million, five hundred seventy-two thousand, one hundred fifty-four".