21298977 has 48 divisors (see below), whose sum is σ = 38905920. Its totient is φ = 11442816.

The previous prime is 21298931. The next prime is 21298987. The reversal of 21298977 is 77989212.

It is not a de Polignac number, because 21298977 - 2¹⁰ = 21297953 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21298987) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 22018 + ... + 22964.

It is an arithmetic number, because the mean of its divisors is an integer number (810540).

Almost surely, 2^21298977 is an apocalyptic number.

21298977 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

It is an amenable number.

21298977 is a deficient number, since it is larger than the sum of its proper divisors (17606943).

21298977 is a wasteful number, since it uses less digits than its factorization.

21298977 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 987 (or 974 counting only the distinct ones).

The product of its digits is 127008, while the sum is 45.

The square root of 21298977 is about 4615.0814727370. The cubic root of 21298977 is about 277.1955463013.

The spelling of 21298977 in words is "twenty-one million, two hundred ninety-eight thousand, nine hundred seventy-seven".