21673380 has 24 divisors (see below), whose sum is σ = 60685632. Its totient is φ = 5779552.

The previous prime is 21673367. The next prime is 21673381. The reversal of 21673380 is 8337612.

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

It is not an unprimeable number, because it can be changed into a prime (21673381) 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, 180552 + ... + 180671.

It is an arithmetic number, because the mean of its divisors is an integer number (2528568).

Almost surely, 2^21673380 is an apocalyptic number.

21673380 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21673380 is an abundant number, since it is smaller than the sum of its proper divisors (39012252).

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

21673380 is a wasteful number, since it uses less digits than its factorization.

21673380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 361235 (or 361233 counting only the distinct ones).

The product of its (nonzero) digits is 6048, while the sum is 30.

The square root of 21673380 is about 4655.4677530835. The cubic root of 21673380 is about 278.8103437364.

The spelling of 21673380 in words is "twenty-one million, six hundred seventy-three thousand, three hundred eighty".