21537954 has 32 divisors (see below), whose sum is σ = 48584640. Its totient is φ = 7070976.

The previous prime is 21537937. The next prime is 21537961. The reversal of 21537954 is 45973512.

It is a super-2 number, since 2×21537954² = 927766925012232, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 642 + ... + 6594.

It is an arithmetic number, because the mean of its divisors is an integer number (1518270).

Almost surely, 2^21537954 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21537954, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24292320).

21537954 is an abundant number, since it is smaller than the sum of its proper divisors (27046686).

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

21537954 is a wasteful number, since it uses less digits than its factorization.

21537954 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6031 (or 6025 counting only the distinct ones).

The product of its digits is 37800, while the sum is 36.

The square root of 21537954 is about 4640.9001282079. The cubic root of 21537954 is about 278.2284150038.

The spelling of 21537954 in words is "twenty-one million, five hundred thirty-seven thousand, nine hundred fifty-four".