21630980 has 48 divisors (see below), whose sum is σ = 52179456. Its totient is φ = 7378560.

The previous prime is 21630923. The next prime is 21630991. The reversal of 21630980 is 8903612.

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, 51170 + ... + 51590.

It is an arithmetic number, because the mean of its divisors is an integer number (1087072).

Almost surely, 2^21630980 is an apocalyptic number.

21630980 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21630980 is an abundant number, since it is smaller than the sum of its proper divisors (30548476).

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

21630980 is a wasteful number, since it uses less digits than its factorization.

21630980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 804 (or 802 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 21630980 is about 4650.9117385734. The cubic root of 21630980 is about 278.6284112479.

The spelling of 21630980 in words is "twenty-one million, six hundred thirty thousand, nine hundred eighty".