21980511 has 32 divisors (see below), whose sum is σ = 39180800. Its totient is φ = 11897280.

The previous prime is 21980467. The next prime is 21980513. The reversal of 21980511 is 11508912.

It is not a de Polignac number, because 21980511 - 2⁶ = 21980447 is a prime.

It is a super-2 number, since 2×21980511² = 966285727642242, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21980513) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 531 + ... + 6651.

It is an arithmetic number, because the mean of its divisors is an integer number (1224400).

Almost surely, 2^21980511 is an apocalyptic number.

21980511 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21980511 is a deficient number, since it is larger than the sum of its proper divisors (17200289).

21980511 is a wasteful number, since it uses less digits than its factorization.

21980511 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6156 (or 6150 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 27.

The square root of 21980511 is about 4688.3377651360. The cubic root of 21980511 is about 280.1211677961.

The spelling of 21980511 in words is "twenty-one million, nine hundred eighty thousand, five hundred eleven".