21977040 has 40 divisors (see below), whose sum is σ = 68129568. Its totient is φ = 5860480.

The previous prime is 21977027. The next prime is 21977063. The reversal of 21977040 is 4077912.

It is a tau number, because it is divible by the number of its divisors (40).

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

It is a junction number, because it is equal to n+sod(n) for n = 21976989 and 21977007.

It is a congruent number.

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, 45546 + ... + 46025.

Almost surely, 2^21977040 is an apocalyptic number.

21977040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21977040 is an abundant number, since it is smaller than the sum of its proper divisors (46152528).

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

21977040 is a wasteful number, since it uses less digits than its factorization.

21977040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91587 (or 91581 counting only the distinct ones).

The product of its (nonzero) digits is 3528, while the sum is 30.

The square root of 21977040 is about 4687.9675766797. The cubic root of 21977040 is about 280.1064221311.

The spelling of 21977040 in words is "twenty-one million, nine hundred seventy-seven thousand, forty".