21097470 has 16 divisors (see below), whose sum is σ = 50634000. Its totient is φ = 5625984.

The previous prime is 21097469. The next prime is 21097481. The reversal of 21097470 is 7479012.

It is a Harshad number since it is a multiple of its sum of digits (30), and also a Moran number because the ratio is a prime number: 703249 = 21097470 / (2 + 1 + 0 + 9 + 7 + 4 + 7 + 0).

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, 351595 + ... + 351654.

It is an arithmetic number, because the mean of its divisors is an integer number (3164625).

Almost surely, 2^21097470 is an apocalyptic number.

21097470 is an abundant number, since it is smaller than the sum of its proper divisors (29536530).

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

21097470 is a wasteful number, since it uses less digits than its factorization.

21097470 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 703259.

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

The square root of 21097470 is about 4593.1982321690. The cubic root of 21097470 is about 276.3186039288.

The spelling of 21097470 in words is "twenty-one million, ninety-seven thousand, four hundred seventy".