21942570 has 32 divisors (see below), whose sum is σ = 56714112. Its totient is φ = 5401152.

The previous prime is 21942539. The next prime is 21942577. The reversal of 21942570 is 7524912.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21942577) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27742 + ... + 28521.

It is an arithmetic number, because the mean of its divisors is an integer number (1772316).

Almost surely, 2^21942570 is an apocalyptic number.

21942570 is an abundant number, since it is smaller than the sum of its proper divisors (34771542).

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

21942570 is a wasteful number, since it uses less digits than its factorization.

21942570 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56286.

The product of its (nonzero) digits is 5040, while the sum is 30.

The square root of 21942570 is about 4684.2897006910. The cubic root of 21942570 is about 279.9599007202.

The spelling of 21942570 in words is "twenty-one million, nine hundred forty-two thousand, five hundred seventy".