21542774 has 16 divisors (see below), whose sum is σ = 37326096. Its totient is φ = 9216000.

The previous prime is 21542771. The next prime is 21542777. The reversal of 21542774 is 47724512.

It is an interprime number because it is at equal distance from previous prime (21542771) and next prime (21542777).

It is a super-2 number, since 2×21542774² = 928182223230152, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21542774.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21542771) 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, 28427 + ... + 29174.

It is an arithmetic number, because the mean of its divisors is an integer number (2332881).

Almost surely, 2^21542774 is an apocalyptic number.

21542774 is a deficient number, since it is larger than the sum of its proper divisors (15783322).

21542774 is a wasteful number, since it uses less digits than its factorization.

21542774 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57631.

The product of its digits is 15680, while the sum is 32.

The square root of 21542774 is about 4641.4193949696. The cubic root of 21542774 is about 278.2491684596.

The spelling of 21542774 in words is "twenty-one million, five hundred forty-two thousand, seven hundred seventy-four".