21572130 has 16 divisors (see below), whose sum is σ = 51773184. Its totient is φ = 5752560.

The previous prime is 21572119. The next prime is 21572141. The reversal of 21572130 is 3127512.

It is an interprime number because it is at equal distance from previous prime (21572119) and next prime (21572141).

It is a junction number, because it is equal to n+sod(n) for n = 21572097 and 21572106.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 359506 + ... + 359565.

It is an arithmetic number, because the mean of its divisors is an integer number (3235824).

Almost surely, 2^21572130 is an apocalyptic number.

21572130 is an abundant number, since it is smaller than the sum of its proper divisors (30201054).

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

21572130 is a wasteful number, since it uses less digits than its factorization.

21572130 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 719081.

The product of its (nonzero) digits is 420, while the sum is 21.

The square root of 21572130 is about 4644.5807130461. The cubic root of 21572130 is about 278.3754996853.

Adding to 21572130 its reverse (3127512), we get a palindrome (24699642).

The spelling of 21572130 in words is "twenty-one million, five hundred seventy-two thousand, one hundred thirty".